drm/radeon: Use RMW accessors for changing LNKCTL

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Don't assume that only the driver would be accessing LNKCTL. ASPM policy
changes can trigger write to LNKCTL outside of driver's control.  And in
the case of upstream bridge, the driver does not even own the device it's
changing the registers for.

Use RMW capability accessors which do proper locking to avoid losing
concurrent updates to the register value.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Fixes: 8a7cd27679 ("drm/radeon/cik: add support for pcie gen1/2/3 switching")
Fixes: b9d305dfb6 ("drm/radeon: implement pcie gen2/3 support for SI")
Link: https://lore.kernel.org/r/20230717120503.15276-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

Ilpo Järvinen 2023-07-17 15:04:58 +03:00 • committed by Bjorn Helgaas

parent ce7d88110b

commit 7189576e8a

2 changed files with 20 additions and 53 deletions

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36

drivers/gpu/drm/radeon/cik.c

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37

drivers/gpu/drm/radeon/si.c

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