Hi,
Am 06.07.21 um 11:58 schrieb Maxime Ripard:
Hi,
On Mon, Jul 05, 2021 at 11:36:34PM +0200, Stefan Wahren wrote:
Commit "drm/vc4: hdmi: Convert to gpiod" changes the behavior of vc4_hdmi_connector_detect() which results into CPU hangs in case there is no HDMI connected. Let's restore the old behavior.
Reported-by: Nathan Chancellor nathan@kernel.org Reported-by: Ojaswin Mujoo ojaswin98@gmail.com Fixes: 6800234ceee0 ("drm/vc4: hdmi: Convert to gpiod") Signed-off-by: Stefan Wahren stefan.wahren@i2se.com
I already sent this patch last week:
https://lore.kernel.org/dri-devel/20210628124257.140453-3-maxime@cerno.tech/
oops, i only looked in the July archive.
I'm not entirely sure how this could create a CPU hang though. Withouth this patch, if the HPD GPIO is low, we would first try to retrieve the EDID, and then if it doesn't we would read the hotplug register.
Yes, the real issue has been revealed by the original change and this patch only "hides" it again.
The first is using a separate i2c controller (and even if it was in the same power domain, we have the pm_runtime_resume call), and the register read should be fine too?
Sorry, i don't have a clue and time for further investigations.
Does it mean, you are not able to reproduce this issue?
Best regards
Maxime