On Fri, Apr 23, 2021 at 1:00 PM Douglas Anderson dianders@chromium.org wrote:
It doesn't make sense to go out to the bus and read the EDID over and over again. Let's cache it and throw away the cache when we turn power off from the panel. Autosuspend means that even if there are several calls to read the EDID before we officially turn the power on then we should get good use out of this cache.
I think i915 caches the edid once on init and never refreshes it (assuming no hotplugs). That said, I think it makes sense for a more conservative approach in panel-simple.
Signed-off-by: Douglas Anderson dianders@chromium.org Reviewed-by: Bjorn Andersson bjorn.andersson@linaro.org
(no changes since v1)
drivers/gpu/drm/panel/panel-simple.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c index a12dfe8b8d90..9be050ab372f 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -189,6 +189,8 @@ struct panel_simple { struct gpio_desc *enable_gpio; struct gpio_desc *hpd_gpio;
struct edid *edid;struct drm_display_mode override_mode; enum drm_panel_orientation orientation;@@ -345,6 +347,9 @@ static int panel_simple_suspend(struct device *dev) regulator_disable(p->supply); p->unprepared_time = ktime_get();
kfree(p->edid);p->edid = NULL;return 0;}
@@ -510,15 +515,13 @@ static int panel_simple_get_modes(struct drm_panel *panel,
/* probe EDID if a DDC bus is available */ if (p->ddc) {
struct edid *edid;pm_runtime_get_sync(panel->dev);edid = drm_get_edid(connector, p->ddc);if (edid) {num += drm_add_edid_modes(connector, edid);kfree(edid);}
if (!p->edid)p->edid = drm_get_edid(connector, p->ddc);if (p->edid)num += drm_add_edid_modes(connector, p->edid);
I suppose this would keep banging on the ddc if drm_get_edid() continuously returns NULL, but maybe that's desireable (it'll succeed sometime in the future)? At any rate, this is an improvement on current behavior so it has my vote.
Reviewed-by: Sean Paul seanpaul@chromium.org
pm_runtime_mark_last_busy(panel->dev); pm_runtime_put_autosuspend(panel->dev);-- 2.31.1.498.g6c1eba8ee3d-goog
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel