- 01 Aug, 2017 40 commits
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Daniel Vetter authored
There's a bunch of folks who're trying to make printk less contended and faster, but there's a problem: printk uses the console_lock, and the console lock has become the BKL for all things fbdev/fbcon, which in turn pulled in half the drm subsystem under that lock. That's awkward. There reasons for that is probably just a historical accident: - fbcon is a runtime option of fbdev, i.e. at runtime you can pick whether your fbdev driver instances are used as kernel consoles. Unfortunately this wasn't implemented with some module option, but through some module loading magic: As long as you don't load fbcon.ko, there's no fbdev console support, but loading it (in any order wrt fbdev drivers) will create console instances for all fbdev drivers. - This was implemented through a notifier chain. fbcon.ko enumerates all fbdev instances at load time and also registers itself as listener in the fbdev notifier. The fbdev core tries to register new fbdev instances with fbcon using the notifier. - On top of that the modifier chain is also used at runtime by the fbdev subsystem to e.g. control backlights for panels. - The problem is that the notifier puts a mutex locking context between fbdev and fbcon, which mixes up the locking contexts for both the runtime usage and the register time usage to notify fbcon. And at runtime fbcon (through the fbdev core) might call into the notifier from a printk critical section while console_lock is held. - This means console_lock must be an outer lock for the entire fbdev subsystem, which also means it must be acquired when registering a new framebuffer driver as the outermost lock since we might call into fbcon (through the notifier) which would result in a locking inversion if fbcon would acquire the console_lock from its notifier callback (which it needs to register the console). - console_lock can be held anywhere, since printk can be called anywhere, and through the above story, plus drm/kms being an fbdev driver, we pull in a shocking amount of locking hiercharchy underneath the console_lock. Which makes cleaning up printk really hard (not even splitting console_lock into an rwsem is all that useful due to this). There's various ways to address this, but the cleanest would be to make fbcon a compile-time option, where fbdev directly calls the fbcon register functions from register_framebuffer, or dummy static inline versions if fbcon is disabled. Maybe augmented with a runtime knob to disable fbcon, if that's needed (for debugging perhaps). But this could break some users who rely on the magic "loading fbcon.ko enables/disables fbdev framebuffers at runtime" thing, even if that's unlikely. Hence we must be careful: 1. Create a compile-time dependency between fbcon and fbdev in the least minimal way. This is what this patch does. 2. Wait at least 1 year to give possible users time to scream about how we broke their setup. Unlikely, since all distros make fbcon compile-in, and embedded platforms only compile stuff they know they need anyway. But still. 3. Convert the notifier to direct functions calls, with dummy static inlines if fbcon is disabled. We'll still need the fb notifier for the other uses (like backlights), but we can probably move it into the fb core (atm it must be built-into vmlinux). 4. Push console_lock down the call-chain, until it is down in console_register again. 5. Finally start to clean up and rework the printk/console locking. For context of this saga see commit 50e244cc Author: Alan Cox <alan@linux.intel.com> Date: Fri Jan 25 10:28:15 2013 +1000 fb: rework locking to fix lock ordering on takeover plus the pile of commits on top that tried to make this all work without terminally upsetting lockdep. We've uncovered all this when console_lock lockdep annotations where added in commit daee7797 Author: Daniel Vetter <daniel.vetter@ffwll.ch> Date: Sat Sep 22 19:52:11 2012 +0200 console: implement lockdep support for console_lock On the patch itself: - Switch CONFIG_FRAMEBUFFER_CONSOLE to be a boolean, using the overall CONFIG_FB tristate to decided whether it should be a module or built-in. - At first I thought I could force the build depency with just a dummy symbol that fbcon.ko exports and fb.ko uses. But that leads to a module depency cycle (it works fine when built-in). Since this tight binding is the entire goal the simplest solution is to move all the fbcon modules (and there's a bunch of optinal source-files which are each modules of their own, for no good reason) into the overall fb.ko core module. That's a bit more than what I would have liked to do in this patch, but oh well. Signed-off-by:
Daniel Vetter <daniel.vetter@intel.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Reviewed-by:
Sean Paul <seanpaul@chromium.org> Signed-off-by:
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 11790 1913 0 13703 3587 drivers/video/fbdev/vt8623fb.o File size after adding 'const': text data bss dec hex filename 11854 1849 0 13703 3587 drivers/video/fbdev/vt8623fb.o Signed-off-by:
Arvind Yadav <arvind.yadav.cs@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Antonino Daplas <adaplas@gmail.com> Cc: Maik Broemme <mbroemme@libmpq.org> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 19884 3036 96 23016 59e8 fbdev/matrox/matroxfb_base.o File size after adding 'const': text data bss dec hex filename 20300 2620 96 23016 59e8 fbdev/matrox/matroxfb_base.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 10332 596 16 10944 2ac0 drivers/video/fbdev/pm3fb.o File size after adding 'const': text data bss dec hex filename 10396 532 16 10944 2ac0 drivers/video/fbdev/pm3fb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 20994 2440 8 23442 5b92 drivers/video/fbdev/s3fb.o File size after adding 'const': text data bss dec hex filename 21506 1928 8 23442 5b92 drivers/video/fbdev/s3fb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 12766 1064 21 13851 361b drivers/video/fbdev/neofb.o File size after adding 'const': text data bss dec hex filename 13086 744 21 13851 361b drivers/video/fbdev/neofb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 2643 1616 16 4275 10b3 video/fbdev/geode/gxfb_core.o File size after adding 'const': text data bss dec hex filename 2707 1552 16 4275 10b3 video/fbdev/geode/gxfb_core.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 11940 660 16 12616 3148 drivers/video/fbdev/pm2fb.o File size after adding 'const': text data bss dec hex filename 12068 532 16 12616 3148 drivers/video/fbdev/pm2fb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 6736 856 0 7592 1da8 drivers/video/fbdev/imsttfb.o File size after adding 'const': text data bss dec hex filename 6832 760 0 7592 1da8 drivers/video/fbdev/imsttfb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 170 488 0 658 292 drivers/video/fbdev/sunxvr500.o File size after adding 'const': text data bss dec hex filename 394 264 0 658 292 drivers/video/fbdev/sunxvr500.o Signed-off-by: -
Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 8432 1456 16 9904 26b0 drivers/video/fbdev/tdfxfb.o File size after adding 'const': text data bss dec hex filename 8560 1328 16 9904 26b0 drivers/video/fbdev/tdfxfb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 7326 1320 0 8646 21c6 fbdev/mb862xx/mb862xxfbdrv.o File size after adding 'const': text data bss dec hex filename 7454 1192 0 8646 21c6 fbdev/mb862xx/mb862xxfbdrv.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 12149 768 36 12953 3299 video/fbdev/nvidia/nvidia.o File size after adding 'const': text data bss dec hex filename 12213 704 36 12953 3299 video/fbdev/nvidia/nvidia.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 7953 568 96 8617 21a9 fbdev/vermilion/vermilion.o File size after adding 'const': text data bss dec hex filename 8017 504 96 8617 21a9 fbdev/vermilion/vermilion.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 3190 2704 24 5918 171e video/fbdev/kyro/fbdev.o File size after adding 'const': text data bss dec hex filename 3290 2640 24 5918 171e video/fbdev/kyro/fbdev.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 12511 1920 0 14431 385f drivers/video/fbdev/arkfb.o File size after adding 'const': text data bss dec hex filename 12607 1824 0 14431 385f drivers/video/fbdev/arkfb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 13132 520 56 13708 358c video/fbdev/i810/i810_main.o File size after adding 'const': text data bss dec hex filename 13356 296 56 13708 358c video/fbdev/i810/i810_main.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 13285 2080 3 15368 3c08 video/fbdev/riva/fbdev.o File size after adding 'const': text data bss dec hex filename 14677 688 3 15368 3c08 video/fbdev/riva/fbdev.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 19916 1240 8 21164 52ac fbdev/savage/savagefb_driver.o File size after adding 'const': text data bss dec hex filename 20684 472 8 21164 52ac fbdev/savage/savagefb_driver.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 3856 968 128 4952 1358 video/fbdev/via/via-core.o File size after adding 'const': text data bss dec hex filename 4304 520 128 4952 1358 video/fbdev/via/via-core.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 13206 1232 40 14478 388e video/fbdev/tridentfb.o File size after adding 'const': text data bss dec hex filename 13910 528 40 14478 388e video/fbdev/tridentfb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 5155 1312 40 6507 196b drivers/video/fbdev/pvr2fb.o File size after adding 'const': text data bss dec hex filename 5219 1248 40 6507 196b drivers/video/fbdev/pvr2fb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 11749 896 24 12669 317d video/fbdev/intelfb/intelfbdrv.o File size after adding 'const': text data bss dec hex filename 12173 472 24 12669 317d video/fbdev/intelfb/intelfbdrv.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 4703 512 0 5215 145f drivers/video/fbdev/asiliantfb.o File size after adding 'const': text data bss dec hex filename 4767 448 0 5215 145f drivers/video/fbdev/asiliantfb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 390 552 0 942 3ae drivers/video/fbdev/sunxvr2500.o File size after adding 'const': text data bss dec hex filename 686 256 0 942 3ae drivers/video/fbdev/sunxvr2500.o Signed-off-by: -
Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 11525 2048 8 13581 350d video/fbdev/aty/aty128fb.o File size after adding 'const': text data bss dec hex filename 13061 512 8 13581 350d video/fbdev/aty/aty128fb.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 17534 1824 48 19406 4bce video/fbdev/aty/atyfb_base.o File size after adding 'const': text data bss dec hex filename 18686 672 48 19406 4bce video/fbdev/aty/atyfb_base.o Signed-off-by:
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Arvind Yadav authored
pci_device_id are not supposed to change at runtime. All functions working with pci_device_id provided by <linux/pci.h> work with const pci_device_id. So mark the non-const structs as const. File size before: text data bss dec hex filename 19709 5024 32 24765 60bd video/fbdev/aty/radeon_base.o File size after adding 'const': text data bss dec hex filename 22893 1840 32 24765 60bd video/fbdev/aty/radeon_base.o Signed-off-by:
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Arvind Yadav authored
attribute_group are not supposed to change at runtime. All functions working with attribute_group provided by <linux/sysfs.h> work with const attribute_group. So mark the non-const structs as const. File size before: text data bss dec hex filename 5227 560 0 5787 169b panel-sony-acx565akm File size after adding 'const': text data bss dec hex filename 5291 496 0 5787 169b panel-sony-acx565akm.o Signed-off-by:
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Arvind Yadav authored
attribute_group are not supposed to change at runtime. All functions working with attribute_group provided by <linux/sysfs.h> work with const attribute_group. So mark the non-const structs as const. File size before: text data bss dec hex filename 2673 368 0 3041 be1 panel-tpo-td043mtea1.o File size after adding 'const': text data bss dec hex filename 2737 304 0 3041 be1 panel-tpo-td043mtea1.o Signed-off-by:
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Arvind Yadav authored
attribute_group are not supposed to change at runtime. All functions working with attribute_group provided by <linux/sysfs.h> work with const attribute_group. So mark the non-const structs as const. File size before: text data bss dec hex filename 15426 4952 187 20565 5055 drivers/video/fbdev/uvesafb.o File size after adding 'const': text data bss dec hex filename 15490 4888 187 20565 5055 drivers/video/fbdev/uvesafb.o Signed-off-by:
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Gustavo A. R. Silva authored
This dev_pm_ops structure is only stored in the pm field of a device_driver structure. This field is declared const, so dev_pm_ops structures that have this property can be declared as const also. Signed-off-by:
Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by:
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Julia Lawall authored
Drop static on a local variable, when the variable is initialized before any possible use. Thus, the static has no benefit. The semantic patch that fixes this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @bad exists@ position p; identifier x; type T; @@ static T x@p; ... x = <+...x...+> @@ identifier x; expression e; type T; position p != bad.p; @@ -static T x@p; ... when != x when strict ?x = e; // </smpl> Signed-off-by:
Julia Lawall <Julia.Lawall@lip6.fr> Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
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Bhumika Goyal authored
Make lcd_panel structure const as it is only copied to some object. As the only usage of this structure is a copy operation, so it can be made const. Signed-off-by:
Bhumika Goyal <bhumirks@gmail.com> Cc: Julia Lawall <julia.lawall@lip6.fr> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by:
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Gustavo A. R. Silva authored
This structure is only used to copy into other structures, so declare it as const. This issue was detected using Coccinelle and the following semantic patch: @r disable optional_qualifier@ identifier i; position p; @@ static struct fb_fix_screeninfo i@p = { ... }; @ok@ identifier r.i; expression e; position p; @@ e = i@p @bad@ position p != {r.p,ok.p}; identifier r.i; struct fb_fix_screeninfo e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct fb_fix_screeninfo i = { ... }; Signed-off-by:Gustavo A. R. Silva <garsilva@embeddedor.com> Signed-off-by:
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Gustavo A. R. Silva authored
These structures are only used to copy into other structures, so declare them as const. This issue was detected using Coccinelle and the following semantic patch: @r disable optional_qualifier@ identifier i; position p; @@ static struct fb_fix_screeninfo i@p = { ... }; @ok@ identifier r.i; expression e; position p; @@ e = i@p @bad@ position p != {r.p,ok.p}; identifier r.i; struct fb_fix_screeninfo e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct fb_fix_screeninfo i = { ... }; The semantic patch for fb_var_screeninfo is analogous. Signed-off-by:Michal Simek <michal.simek@xilinx.com> Cc: Soren Brinkmann <soren.brinkmann@xilinx.com> Signed-off-by:
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Gustavo A. R. Silva authored
These structures are only used to copy into other structures, so declare them as const. This issue was detected using Coccinelle and the following semantic patch: @r disable optional_qualifier@ identifier i; position p; @@ static struct fb_fix_screeninfo i@p = { ... }; @ok@ identifier r.i; expression e; position p; @@ e = i@p @bad@ position p != {r.p,ok.p}; identifier r.i; struct fb_fix_screeninfo e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct fb_fix_screeninfo i = { ... }; The semantic patch for fb_var_screeninfo is analogous. Signed-off-by: -
Gustavo A. R. Silva authored
These structures are only used to copy into other structures, so declare them as const. This issue was detected using Coccinelle and the following semantic patch: @r disable optional_qualifier@ identifier i; position p; @@ static struct fb_fix_screeninfo i@p = { ... }; @ok@ identifier r.i; expression e; position p; @@ e = i@p @bad@ position p != {r.p,ok.p}; identifier r.i; struct fb_fix_screeninfo e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct fb_fix_screeninfo i = { ... }; The semantic patch for fb_var_screeninfo is analogous. Signed-off-by: -
Lynn Lei authored
Fixed a constant-left comparison warning issue check by scripts/checkpatch.pl: WARNING: Comparisons should place the constant on the right side of the test Signed-off-by:
Lynn Lei <lynnl.wit@gmail.com> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Cc: Teddy Wang <teddy.wang@siliconmotion.com> Signed-off-by:
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