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Fabio Estevam authored
Commit a71e3c37 ("net: phy: Set the driver when registering an MDIO bus device") caused the following regression on the fec driver: root@imx6qsabresd:~# echo mem > /sys/power/state PM: Syncing filesystems ... done. Freezing user space processes ... (elapsed 0.003 seconds) done. Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done. Unable to handle kernel NULL pointer dereference at virtual address 0000002c pgd = bcd14000 [0000002c] *pgd=4d9e0831, *pte=00000000, *ppte=00000000 Internal error: Oops: 17 [#1] SMP ARM Modules linked in: CPU: 0 PID: 617 Comm: sh Not tainted 3.16.0 #17 task: bc0c4e00 ti: bceb6000 task.ti: bceb6000 PC is at fec_suspend+0x10/0x70 LR is at dpm_run_callback.isra.7+0x34/0x6c pc : [<803f8a98>] lr : [<80361f44>] psr: 600f0013 sp : bceb7d70 ip : bceb7d88 fp : bceb7d84 r10: 8091523c r9 : 00000000 r8 : bd88f478 r7 : 803f8a88 r6 : 81165988 r5 : 00000000 r4 : 00000000 r3 : 00000000 r2 : 00000000 r1 : bd88f478 r0 : bd88f478 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5387d Table: 4cd1404a DAC: 00000015 Process sh (pid: 617, stack limit = 0xbceb6240) Stack: (0xbceb7d70 to 0xbceb8000) .... The problem with the original commit is explained by Russell King: "It has the effect (as can be seen from the oops) of attaching the MDIO bus device (itself is a bus-less device) to the platform driver, which means that if the platform driver supports power management, it will be called to power manage the MDIO bus device. Moreover, drivers do not expect to be called for power management operations for devices which they haven't probed, and certainly not for devices which aren't part of the same bus that the driver is registered against." This reverts commit a71e3c37. Cc: <stable@vger.kernel.org> #3.16 Signed-off-by:
Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
ce7991e8