drm/radeon: add hard_reset module parameter

Enabling this parameter enables pci config reset,
aka hard reset, which is a bus level chip reset.
In some cases this works more reliably than a soft
reset.  Disabled by default.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon.h

@@ -99,6 +99,7 @@ extern int radeon_fastfb;
 extern int radeon_dpm;
 extern int radeon_aspm;
 extern int radeon_runtime_pm;
+extern int radeon_hard_reset;
 
 /*
  * Copy from radeon_drv.h so we don't have to include both and have conflicting

drivers/gpu/drm/radeon/radeon_drv.c

@@ -167,6 +167,7 @@ int radeon_fastfb = 0;
 int radeon_dpm = -1;
 int radeon_aspm = -1;
 int radeon_runtime_pm = -1;
+int radeon_hard_reset = 0;
 
 MODULE_PARM_DESC(no_wb, "Disable AGP writeback for scratch registers");
 module_param_named(no_wb, radeon_no_wb, int, 0444);
@@ -231,6 +232,9 @@ module_param_named(aspm, radeon_aspm, int, 0444);
 MODULE_PARM_DESC(runpm, "PX runtime pm (1 = force enable, 0 = disable, -1 = PX only default)");
 module_param_named(runpm, radeon_runtime_pm, int, 0444);
 
+MODULE_PARM_DESC(hard_reset, "PCI config reset (1 = force enable, 0 = disable (default))");
+module_param_named(hard_reset, radeon_hard_reset, int, 0444);
+
 static struct pci_device_id pciidlist[] = {
 	radeon_PCI_IDS
 };