From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org, stable@vger.kernel.org
Subject: Re: [Intel-gfx] [PATCH] drm/i915/gt: Program mocs:63 for cache eviction on gen9
Date: Thu, 26 Nov 2020 16:08:24 +0200 [thread overview]
Message-ID: <20201126140824.GC6112@intel.com> (raw)
In-Reply-To: <20201126105539.2661-1-chris@chris-wilson.co.uk>
On Thu, Nov 26, 2020 at 10:55:39AM +0000, Chris Wilson wrote:
> Ville noticed that the last mocs entry is used unconditionally by the HW
> when it performs cache evictions, and noted that while the value is not
> meant to be writable by the driver, we should program it to a reasonable
> value nevertheless.
>
> As it turns out, we can change the value of mocs:63 and the value we
> were programming into it would cause hard hangs in conjunction with
> atomic operations.
>
> Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2707
> Fixes: 3bbaba0ceaa2 ("drm/i915: Added Programming of the MOCS")
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Jason Ekstrand <jason@jlekstrand.net>
> Cc: <stable@vger.kernel.org> # v4.3+
> ---
> drivers/gpu/drm/i915/gt/intel_mocs.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_mocs.c b/drivers/gpu/drm/i915/gt/intel_mocs.c
> index 254873e1646e..6ae512847f64 100644
> --- a/drivers/gpu/drm/i915/gt/intel_mocs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_mocs.c
> @@ -131,7 +131,10 @@ static const struct drm_i915_mocs_entry skl_mocs_table[] = {
> GEN9_MOCS_ENTRIES,
> MOCS_ENTRY(I915_MOCS_CACHED,
> LE_3_WB | LE_TC_2_LLC_ELLC | LE_LRUM(3),
> - L3_3_WB)
> + L3_3_WB),
> + MOCS_ENTRY(63,
Wonder if we should give these magic MOCS entries actual names?
Anyways, matches my reading of the spec
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> + LE_3_WB | LE_TC_1_LLC | LE_LRUM(3),
> + L3_1_UC)
> };
>
> /* NOTE: the LE_TGT_CACHE is not used on Broxton */
> --
> 2.20.1
--
Ville Syrjälä
Intel
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next prev parent reply other threads:[~2020-11-26 14:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-26 10:55 [Intel-gfx] [PATCH] drm/i915/gt: Program mocs:63 for cache eviction on gen9 Chris Wilson
2020-11-26 12:54 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
2020-11-26 13:24 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-11-26 14:08 ` Ville Syrjälä [this message]
2020-11-26 14:13 ` [Intel-gfx] [PATCH] " Chris Wilson
2020-11-26 14:08 ` Chris Wilson
2020-11-26 15:50 ` Ville Syrjälä
2021-01-25 21:39 ` Jason Ekstrand
2020-11-26 15:10 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gt: Program mocs:63 for cache eviction on gen9 (rev2) Patchwork
2020-11-26 15:40 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-11-26 18:02 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
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