On Tue, Jul 06, 2021 at 05:45:27PM +0200, Stefan Wahren wrote: > Hi Maxime, > > Am 06.07.21 um 15:21 schrieb Maxime Ripard: > > Hi Stefan, > > > > On Tue, Jul 06, 2021 at 12:48:05PM +0200, Stefan Wahren wrote: > >> 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 > >>>> Reported-by: Ojaswin Mujoo > >>>> Fixes: 6800234ceee0 ("drm/vc4: hdmi: Convert to gpiod") > >>>> Signed-off-by: Stefan Wahren > >>> 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? > > On next-20210706 at least it works fine for me without an HDMI monitor > > connected, yes: > > which configuration do you use? Did you tried arm/multi_v7_defconfig? > > I tried yesterday mainline ("a180bd1d7e16173d965b263c5a536aa40afa2a2a") > with multi_v7_defconfig and the issue was there. I can't boot multi_v7_defconfig on my setup, but I just tested multi_v7 + a few options (UART, ethernet) built-in to be able to boot, and I can't reproduce what you're seeing. It boots just fine without any monitor attached. Maxime