On 04/05/2022 19:17, Matt Roper wrote:
On Wed, May 04, 2022 at 06:59:32PM +0100, Tvrtko Ursulin wrote:
On 04/05/2022 17:48, Matt Roper wrote:
On Wed, May 04, 2022 at 01:07:14PM +0100, Tvrtko Ursulin wrote:
From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
DRM_DEBUG_WARN_ON should only be used when we are certain CI is guaranteed
to exercise a certain code path, so in case of values coming from MMIO
reads we cannot be sure CI will have all the possible SKUs and parts.
Use drm_warn instead and move logging to init phase while at it.
Changing to drm_warn looks good, although moving the location changes
the intent a bit; I think originally the idea was to warn if we were
trying to do a steering lookup for a type that we never initialized
(e.g., an LNCF lookup for a !HAS_MSLICES platform where we never even
read the register in the first place). But I don't think we've ever
made a mistake that would cause us to trip the warning, so it probably
isn't terribly important to keep it there.
Ah I see.. there we could put something like:
case MSLICE:
GEM_WARN_ON(!HAS_MSLICES(...));
Yeah, that would work for MSLICE and LNCF. Although L3BANK is a bit
stranger since we have multiple platforms that obtain the L3 bank mask
in completely different ways (Xe_HP reads it from XEHP_FUSE4, whereas
gen11/gen12 reads it from GEN10_MIRROR_FUSE3). We want to make sure
there that no matter which branch of init we take, we didn't forget to
initialize l3bank_mask somehow.
The two init paths are not something present in drm-tip at this point,
right? At least I couldn't find it. In which case it could be handled
later by moving the drm_warn to tail of intel_gt_init_mmio, give or take.
Anyway, I've sent v2 out with your r-b and GEM_WARN_ON for mslice/lncf.
I won't merge it though until you definitely are okay with it so please
have a look and confirm.
Regards,
Tvrtko
Matt
?
Regards,
Tvrtko
Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_gt.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index 53307ca0eed0..c474e5c3ea5e 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -153,11 +153,14 @@ int intel_gt_init_mmio(struct intel_gt *gt)
* An mslice is unavailable only if both the meml3 for the slice is
* disabled *and* all of the DSS in the slice (quadrant) are disabled.
*/
- if (HAS_MSLICES(i915))
+ if (HAS_MSLICES(i915)) {
gt->info.mslice_mask =
slicemask(gt, GEN_DSS_PER_MSLICE) |
(intel_uncore_read(gt->uncore, GEN10_MIRROR_FUSE3) &
GEN12_MEML3_EN_MASK);
+ if (!gt->info.mslice_mask) /* should be impossible! */
+ drm_warn(&i915->drm, "mslice mask all zero!\n");
+ }
if (IS_DG2(i915)) {
gt->steering_table[MSLICE] = xehpsdv_mslice_steering_table;
@@ -171,6 +174,8 @@ int intel_gt_init_mmio(struct intel_gt *gt)
gt->info.l3bank_mask =
~intel_uncore_read(gt->uncore, GEN10_MIRROR_FUSE3) &
GEN10_L3BANK_MASK;
+ if (!gt->info.l3bank_mask) /* should be impossible! */
+ drm_warn(&i915->drm, "L3 bank mask is all zero!\n");
} else if (HAS_MSLICES(i915)) {
MISSING_CASE(INTEL_INFO(i915)->platform);
}
@@ -882,20 +887,14 @@ static void intel_gt_get_valid_steering(struct intel_gt *gt,
{
switch (type) {
case L3BANK:
- GEM_DEBUG_WARN_ON(!gt->info.l3bank_mask); /* should be impossible! */
-
*sliceid = 0; /* unused */
*subsliceid = __ffs(gt->info.l3bank_mask);
break;
case MSLICE:
- GEM_DEBUG_WARN_ON(!gt->info.mslice_mask); /* should be impossible! */
-
*sliceid = __ffs(gt->info.mslice_mask);
*subsliceid = 0; /* unused */
break;
case LNCF:
- GEM_DEBUG_WARN_ON(!gt->info.mslice_mask); /* should be impossible! */
-
/*
* An LNCF is always present if its mslice is present, so we
* can safely just steer to LNCF 0 in all cases.
--
2.32.0
