drm/xe: Handle unreliable MMIO reads during forcewake

[ Upstream commit 69418db678567bdf9a4992c83d448da462ffa78c ]

In some cases, when the driver attempts to read an MMIO register,
the hardware may return 0xFFFFFFFF. The current force wake path
code treats this as a valid response, as it only checks the BIT.
However, 0xFFFFFFFF should be considered an invalid value, indicating
a potential issue. To address this, we should add a log entry to
highlight this condition and return failure.
The force wake failure log level is changed from notice to err
to match the failure return value.

v2 (Matt Brost):
  - set ret value (-EIO) to kick the error to upper layers
v3 (Rodrigo):
  - add commit message for the log level promotion from notice to err
v4:
  - update reviewed info

Suggested-by: Alex Zuo <alex.zuo@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Acked-by: Badal Nilawar <badal.nilawar@intel.com>
Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241017221547.1564029-1-shuicheng.lin@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
(cherry picked from commit a9fbeabe7226a3bf90f82d0e28a02c18e3c67447)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

0 files changed, 0 insertions, 0 deletions