media: cobalt: fix race condition in setting HPD

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The cobalt_s_bit_sysctrl reads the old register value over PCI,
then changes a bit and sets writes the new value to the register.

This is used among other things for setting the HPD output pin.

But if the HPD is changed for multiple inputs at the same time,
then this causes a race condition where a stale value is read.

Serialize this function with a mutex.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

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This commit is contained in:

Hans Verkuil 2021-04-23 10:00:49 +02:00 • committed by Mauro Carvalho Chehab

parent b2cd0b31ed

commit 3d37ef41be

2 changed files with 7 additions and 1 deletions

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1

drivers/media/pci/cobalt/cobalt-driver.c

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7

drivers/media/pci/cobalt/cobalt-driver.h

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