[PATCH 1/3] drm/xe/vf: Don't check has flat ccs in bios on VF

[Marcin Bernatowicz]

From: Jakub Kolakowski <jakub1.kolakowski at intel.com>

Don't check for flat ccs from VF-level as VF does not have direct
access to the register.

If the BIOS disables FlatCCS support (a use-case that will nearly never
be used) and the has_flat_ccs flag is set, there shouldn't be
any functional impact. The hardware will drop writes to the CCS region,
and reads from the CCS region will always return 0.
For the native case, the flag is disabled if the BIOS disables
it to avoid unnecessary overhead in buffer object (BO) creation
and migration.

Signed-off-by: Jakub Kolakowski <jakub1.kolakowski at intel.com>
Suggested-by: Piotr Piórkowski <piotr.piorkowski at intel.com>
Cc: Adam Miszczak <adam.miszczak at linux.intel.com>
Cc: Jakub Kolakowski <jakub1.kolakowski at intel.com>
Cc: Lukasz Laguna <lukasz.laguna at intel.com>
Cc: Marcin Bernatowicz <marcin.bernatowicz at linux.intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Michal Winiarski <michal.winiarski at intel.com>
Cc: Narasimha C V <narasimha.c.v at intel.com>
Cc: Piotr Piorkowski <piotr.piorkowski at intel.com>
Cc: Satyanarayana K V P <satyanarayana.k.v.p at intel.com>
Cc: Tomasz Lis <tomasz.lis at intel.com>
Cc: Matt Roper <matthew.d.roper at intel.com>
Signed-off-by: Marcin Bernatowicz <marcin.bernatowicz at linux.intel.com>
---
 drivers/gpu/drm/xe/xe_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 56d4ffb650da..ec0ea9c914b4 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -604,7 +604,7 @@ static int probe_has_flat_ccs(struct xe_device *xe)
 	u32 reg;
 
 	/* Always enabled/disabled, no runtime check to do */
-	if (GRAPHICS_VER(xe) < 20 || !xe->info.has_flat_ccs)
+	if (GRAPHICS_VER(xe) < 20 || !xe->info.has_flat_ccs || IS_SRIOV_VF(xe))
 		return 0;
 
 	gt = xe_root_mmio_gt(xe);
-- 
2.31.1