On Mon, Sep 12, 2022 at 06:59:53PM +0200, Andi Shyti wrote:
Hi Lucas,
On Mon, Sep 12, 2022 at 09:19:38AM -0700, Lucas De Marchi wrote:
Support for reading the fuses to check what are the Link Copy engines
was added in commit ad5f74f34201 ("drm/i915/pvc: read fuses for link
copy engines"). However they were added unconditionally because the
FUSE3 register is present since graphics version 10.
However the bitfield with meml3 fuses only exists since graphics version
12. Moreover, Link Copy engines are currently only available in PVC.
Tying additional copy engines to the meml3 fuses is not correct for
other platforms.
Make sure there is a check for `12.60 <= ver < 12.70`. Later platforms
may extend this function later if it's needed to fuse off copy engines.
Currently it's harmless as the Link Copy engines are still not exported:
info->engine_mask only has BCS0 set and the register is only read for
platforms that do have it.
Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 814f83b5fe59..1f7188129cd1 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -764,6 +764,10 @@ static void engine_mask_apply_copy_fuses(struct intel_gt *gt)
unsigned long meml3_mask;
unsigned long quad;
+ if (!(GRAPHICS_VER_FULL(i915) >= IP_VER(12, 60) &&
+ GRAPHICS_VER_FULL(i915) < IP_VER(12, 70)))
+ return;
+
Isn't it easier if you wrote
if (GRAPHICS_VER_FULL(i915) < IP_VER(12, 60) ||
GRAPHICS_VER_FULL(i915) >= IP_VER(12, 70))
return;
?
You save a parenthesis and a negation '!'.
but that makes it wrong. I'd really want the range
12.60 <= version < 12.70, so it applies to PVC but is then disabled
again for MTL. Depending on how this evolves for future platforms, we
may change it to a feature flag or just check by platform
name. For now I think this is the most future-proof option.
Lucas De Marchi
Anyway, looks good:
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
Andi
meml3_mask = intel_uncore_read(gt->uncore, GEN10_MIRROR_FUSE3);
meml3_mask = REG_FIELD_GET(GEN12_MEML3_EN_MASK, meml3_mask);
--
b4 0.10.0-dev-df873
