On 27.09.2022 13:12:35, Stefan Wahren wrote: > > > > yes the issue is only triggered without HDMI connected. I was able to > > > > reproduce with an older vc4 firmware from 2020 (don't want to upgrade yet). > > > > Kernel was also an arm64 build with defconfig. > > > > > > > > Here some rough starting point for bisection: > > > > > > > > 5.18.0 good > > > > 5.19.0 bad > > > > 5.19.6 bad > > > Sorry it took a bit of time, it looks like I found another bug while > > > trying to test this yesterday. > > > > > > Your datapoints are interesting though. I have a custom configuration > > > and it does boot 5.19 without an HDMI connected. > > > > > > So I guess it leaves us with either the firmware version being different > > > (I'm using a newer version, from March 2022), or the configuration. I'll > > > test with defconfig. > > So it turns out compiling vc4 as a module is the culprit. > > Do you mean regardless of the kernel version in your case? On Debian vc4 is a module, too, both on 5.18.x (good) and 5.19.6 (bad). > In my test cases i build vc4 always as module. > > > It's not clear to me why at this point, but the first register write in > > vc4_hdmi_reset stalls. > > Sounds like timing issue or a missing dependency (clock or power domain) Here it fails 100%, regardless if the module is automatically loaded by udev or later on an idle system via insmod. regards, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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