From: Chris Wilson <chris@chris-wilson.co.uk>
To: Ville Syrjala <ville.syrjala@linux.intel.com>,
intel-gfx@lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH] drm/i915: Readout conn_state->max_bpc
Date: Tue, 16 Feb 2021 17:25:27 +0000 [thread overview]
Message-ID: <161349632758.8311.6775260061918956330@build.alporthouse.com> (raw)
In-Reply-To: <20210216160035.4780-1-ville.syrjala@linux.intel.com>
Quoting Ville Syrjala (2021-02-16 16:00:35)
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Populate conn_state->max_bpc with something sensible from the start.
> Otherwise it's possible that we get to compute_sink_pipe_bpp() with
> max_bpc==0.
>
> The specific scenario goes as follows:
> 1. Initial connector state allocated with max_bpc==0
> 2. Trigger a modeset on the crtc feeding the connector, without
> actually adding the connector to the commit
> 3. drm_atomic_connector_check() is skipped because the
> connector has not yet been added, hence conn_state->max_bpc
> retains its current value
> 4. drm_atomic_helper_check_modeset() ->
> drm_atomic_add_affected_connectors() -> the connector
> is now part of the commit
> 5. compute_baseline_pipe_bpp() -> MISSING_CASE(max_bpc==0)
>
> Note that pipe_bpp itself may not be populated on pre-g4x machines,
> in which case we just fall back to max_bpc==8 and let .compute_config()
> limit the resulting pipe_bpp further if necessary.
>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris
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next prev parent reply other threads:[~2021-02-16 17:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-16 16:00 [Intel-gfx] [PATCH] drm/i915: Readout conn_state->max_bpc Ville Syrjala
2021-02-16 17:25 ` Chris Wilson [this message]
2021-02-16 17:41 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2021-02-16 19:52 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2021-03-02 19:02 ` [Intel-gfx] [PATCH] " Souza, Jose
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