Reviewed-by: Lyude Paul lyude@redhat.com

On Wed, 2021-07-14 at 09:33 -0700, Douglas Anderson wrote:

When I tried booting up a device that needed the DP AUX backlight, I found an error in the logs:   panel-simple-dp-aux: probe of aux-ti_sn65dsi86.aux.0 failed with error - 110

The aux transfers were failing because the panel wasn't powered. Just like when reading the EDID we need to power the panel when trying to talk to it. Add the needed pm_runtime calls.

After I do this I can successfully probe the panel and adjust the backlight on my board.

Fixes: bfd451403d70 ("drm/panel-simple: Support DP AUX backlight") Signed-off-by: Douglas Anderson dianders@chromium.org

---

drivers/gpu/drm/panel/panel-simple.c | 3 +++  1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c index e0a05f366ce6..9b286bd4444f 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -827,7 +827,10 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc,                 goto disable_pm_runtime;           if (!panel->base.backlight && panel->aux) { +               pm_runtime_get_sync(dev);                 err = drm_panel_dp_aux_backlight(&panel->base, panel->aux); +               pm_runtime_mark_last_busy(dev); +               pm_runtime_put_autosuspend(dev);                 if (err)                         goto disable_pm_runtime;         }