On Thu, Feb 02, 2023 at 07:02:43PM +0100, Nirmoy Das wrote:
DSM granularity is 1MB so make sure we stick to that.
I think we need to be a bit more verbose here, because in future we may need to refer to this commit if/when things change (e.g. the granularity or the additional size needed on top of DSM). The issue this is fixing is that the address set by firmware in GEN12_DSMBASE and read here doesn't mean "anything above it until the of lmem is part of DSM". There may be a few KB that is not part of DSM. How large is that space is platform-dependent, but since it's always less than the DSM granularity, it can be simplified by simply aligning the size like is done here.
v2: replace "1 * SZ_1M" with SZ_1M (Andrzej). Cc: Matthew Auld <matthew.auld@xxxxxxxxx> Suggested-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> Signed-off-by: Nirmoy Das <nirmoy.das@xxxxxxxxx> Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
Reviewed-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> Are you ok with me amending the commit message and applying? After this patch I think you can follow the process to request committer access. Lucas De Marchi
--- drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c index 90a967374b1a..d8e06e783e30 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c @@ -909,7 +909,7 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type, dsm_base = intel_uncore_read64(uncore, GEN12_DSMBASE) & GEN12_BDSM_MASK; if (WARN_ON(lmem_size < dsm_base)) return ERR_PTR(-ENODEV); - dsm_size = lmem_size - dsm_base; + dsm_size = ALIGN_DOWN(lmem_size - dsm_base, SZ_1M); } io_size = dsm_size; -- 2.39.0
