Messages in this thread | | | Date | Wed, 12 Apr 2023 09:08:11 +0200 | From | Matthias Brugger <> | Subject | Re: [PATCH v3 1/9] drm/mediatek: dp: Cache EDID for eDP panel |
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On 04/04/2023 12:47, AngeloGioacchino Del Regno wrote: > Since eDP panels are not removable it is safe to cache the EDID: > this will avoid a relatively long read transaction at every PM > resume that is unnecessary only in the "special" case of eDP, > hence speeding it up a little, as from now on, as resume operation, > we will perform only link training. > > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> > --- > drivers/gpu/drm/mediatek/mtk_dp.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c > index 1f94fcc144d3..84f82cc68672 100644 > --- a/drivers/gpu/drm/mediatek/mtk_dp.c > +++ b/drivers/gpu/drm/mediatek/mtk_dp.c > @@ -118,6 +118,7 @@ struct mtk_dp { > const struct mtk_dp_data *data; > struct mtk_dp_info info; > struct mtk_dp_train_info train_info; > + struct edid *edid; > > struct platform_device *phy_dev; > struct phy *phy; > @@ -1993,7 +1994,11 @@ static struct edid *mtk_dp_get_edid(struct drm_bridge *bridge, > usleep_range(2000, 5000); > } > > - new_edid = drm_get_edid(connector, &mtk_dp->aux.ddc); > + /* eDP panels aren't removable, so we can return a cached EDID. */ > + if (mtk_dp->edid && mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP) > + new_edid = drm_edid_duplicate(mtk_dp->edid); > + else > + new_edid = drm_get_edid(connector, &mtk_dp->aux.ddc);
Maybe it would make sense to add a macro for the check of mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP it would make the code more readable.
> > /* > * Parse capability here to let atomic_get_input_bus_fmts and > @@ -2022,6 +2027,10 @@ static struct edid *mtk_dp_get_edid(struct drm_bridge *bridge, > drm_atomic_bridge_chain_post_disable(bridge, connector->state->state); > } > > + /* If this is an eDP panel and the read EDID is good, cache it for later */ > + if (mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP && !mtk_dp->edid && new_edid) > + mtk_dp->edid = drm_edid_duplicate(new_edid); > +
How about putting this in an else if branch of mtk_dp_parse_capabilities. At least we could get rid of the check regarding if new_edid != NULL.
I was thinking on how to put both if statements in one block, but I think the problem is, that we would leak memory if the capability parsing failes due to the call to drm_edid_duplicate(). Correct?
Regards, Matthais
> return new_edid; > }. / >
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