drm/amdgpu: Use RMW accessors for changing LNKCTL
authorIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Mon, 17 Jul 2023 12:04:57 +0000 (15:04 +0300)
committerBjorn Helgaas <bhelgaas@google.com>
Mon, 21 Aug 2023 19:11:35 +0000 (14:11 -0500)
commitce7d88110b9ed5f33fe79ea6d4ed049fb0e57bce
tree165952b4eb06dd953ec354b73ccbfd3af5dbf266
parente09060b3b6b4661278ff8e1b7b81a37d5ea86eae
drm/amdgpu: Use RMW accessors for changing LNKCTL

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: a2e73f56fa62 ("drm/amdgpu: Add support for CIK parts")
Fixes: 62a37553414a ("drm/amdgpu: add si implementation v10")
Link: https://lore.kernel.org/r/20230717120503.15276-6-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>
drivers/gpu/drm/amd/amdgpu/cik.c
drivers/gpu/drm/amd/amdgpu/si.c