From: Shuicheng Lin <shuicheng....@intel.com>

[ 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....@intel.com>
Signed-off-by: Shuicheng Lin <shuicheng....@intel.com>
Cc: Matthew Brost <matthew.br...@intel.com>
Cc: Michal Wajdeczko <michal.wajdec...@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimi...@intel.com>
Acked-by: Badal Nilawar <badal.nila...@intel.com>
Cc: Anshuman Gupta <anshuman.gu...@intel.com>
Cc: Matt Roper <matthew.d.ro...@intel.com>
Cc: Rodrigo Vivi <rodrigo.v...@intel.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20241017221547.1564029-1-shuicheng....@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.v...@intel.com>
(cherry picked from commit a9fbeabe7226a3bf90f82d0e28a02c18e3c67447)
Signed-off-by: Lucas De Marchi <lucas.demar...@intel.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/gpu/drm/xe/xe_force_wake.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_force_wake.c 
b/drivers/gpu/drm/xe/xe_force_wake.c
index b263fff152737..7d9fc489dcb81 100644
--- a/drivers/gpu/drm/xe/xe_force_wake.c
+++ b/drivers/gpu/drm/xe/xe_force_wake.c
@@ -115,9 +115,15 @@ static int __domain_wait(struct xe_gt *gt, struct 
xe_force_wake_domain *domain,
                             XE_FORCE_WAKE_ACK_TIMEOUT_MS * USEC_PER_MSEC,
                             &value, true);
        if (ret)
-               xe_gt_notice(gt, "Force wake domain %d failed to ack %s (%pe) 
reg[%#x] = %#x\n",
-                            domain->id, str_wake_sleep(wake), ERR_PTR(ret),
-                            domain->reg_ack.addr, value);
+               xe_gt_err(gt, "Force wake domain %d failed to ack %s (%pe) 
reg[%#x] = %#x\n",
+                         domain->id, str_wake_sleep(wake), ERR_PTR(ret),
+                         domain->reg_ack.addr, value);
+       if (value == ~0) {
+               xe_gt_err(gt,
+                         "Force wake domain %d: %s. MMIO unreliable (forcewake 
register returns 0xFFFFFFFF)!\n",
+                         domain->id, str_wake_sleep(wake));
+               ret = -EIO;
+       }
 
        return ret;
 }
-- 
2.43.0

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