drm/xe/guc: Fail immediately on GuC load error

By using the same variable for both the return of poll_timeout_us and
the return of the polled function guc_wait_ucode, the return value of
the latter is overwritten and lost after exiting the polling loop. Since
guc_wait_ucode returns -1 on GuC load failure, we lose that information
and always continue as if the GuC had been loaded correctly.

This is fixed by simply using 2 separate variables.

Fixes: a4916b4 ("drm/xe/guc: Refactor GuC load to use poll_timeout_us()")
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patch.msgid.link/20260303001732.2540493-2-daniele.ceraolospurio@intel.com
(cherry picked from commit c85ec5c)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Author: dceraolo

drivers/gpu/drm/xe/xe_guc.c

@@ -1124,22 +1124,22 @@ static int guc_wait_ucode(struct xe_guc *guc)
 	struct xe_guc_pc *guc_pc = &gt->uc.guc.pc;
 	u32 before_freq, act_freq, cur_freq;
 	u32 status = 0, tries = 0;
+	int load_result, ret;
 	ktime_t before;
 	u64 delta_ms;
-	int ret;
 
 	before_freq = xe_guc_pc_get_act_freq(guc_pc);
 	before = ktime_get();
 
-	ret = poll_timeout_us(ret = guc_load_done(gt, &status, &tries), ret,
+	ret = poll_timeout_us(load_result = guc_load_done(gt, &status, &tries), load_result,
 			      10 * USEC_PER_MSEC,
 			      GUC_LOAD_TIMEOUT_SEC * USEC_PER_SEC, false);
 
 	delta_ms = ktime_to_ms(ktime_sub(ktime_get(), before));
 	act_freq = xe_guc_pc_get_act_freq(guc_pc);
 	cur_freq = xe_guc_pc_get_cur_freq_fw(guc_pc);
 
-	if (ret) {
+	if (ret || load_result <= 0) {
 		xe_gt_err(gt, "load failed: status = 0x%08X, time = %lldms, freq = %dMHz (req %dMHz)\n",
 			  status, delta_ms, xe_guc_pc_get_act_freq(guc_pc),
 			  xe_guc_pc_get_cur_freq_fw(guc_pc));