On Tue, Sep 27, 2022 at 03:15:17PM +0200, Maxime Ripard wrote: > On Tue, Sep 27, 2022 at 02:25:12PM +0200, Maxime Ripard wrote: > > On Tue, Sep 27, 2022 at 01:42:40PM +0200, Maxime Ripard wrote: > > > On Tue, Sep 27, 2022 at 01:12:35PM +0200, Stefan Wahren wrote: > > > > Am 27.09.22 um 11:42 schrieb Maxime Ripard: > > > > > On Tue, Sep 27, 2022 at 09:25:54AM +0200, Maxime Ripard wrote: > > > > > > Hi Stefan, > > > > > > > > > > > > On Mon, Sep 26, 2022 at 08:50:12PM +0200, Stefan Wahren wrote: > > > > > > > Am 26.09.22 um 14:47 schrieb Maxime Ripard: > > > > > > > > On Mon, Sep 26, 2022 at 02:40:48PM +0200, Marc Kleine-Budde wrote: > > > > > > > > > On 26.09.2022 14:08:04, Stefan Wahren wrote: > > > > > > > > > > Hi Marc, > > > > > > > > > > > > > > > > > > > > Am 26.09.22 um 12:21 schrieb Marc Kleine-Budde: > > > > > > > > > > > On 22.09.2022 17:06:00, Maxime Ripard wrote: > > > > > > > > > > > > > I'm on a Raspberry Pi 3 Model B+ running current Debian testing ARM64, > > > > > > > > > > > > > using Debian's v5.19 kernel (Debian's v5.18 was working flawless). > > > > > > > > > > > > > > > > > > > > > > > > > > | [ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd034] > > > > > > > > > > > > > | [ 0.000000] Linux version 5.19.0-1-arm64 (debian-kernel@xxxxxxxxxxxxxxxx) (gcc-11 (Debian 11.3.0-5) 11.3.0, GNU ld (GNU Binutils for Debian) 2.38.90.20220713) #1 SMP Debian 5.19.6-1 (2022-0 > > > > > > > > > > > > > 9-01) > > > > > > > > > > > > > | [ 0.000000] Machine model: Raspberry Pi 3 Model B+ > > > > > > > > > > > > > | [ 3.747500] raspberrypi-firmware soc:firmware: Attached to firmware from 2022-03-24T13:21:11 > > > > > > > > > > > > > > > > > > > > > > > > > > As soon a the vc4 module is loaded the following warnings hits 4 > > > > > > > > > > > > > times, then the machine stops. > > > > > > > > > > > [...] > > > > > > > > > > > > > > > > > > > > > > > The warning itself is fixed, both upstream and in stable (5.19.7). > > > > > > > > > > > Ok. Debian is using 5.19.6 > > > > > > > > > > > > > > > > > > > > > > > It shouldn't have any relation to the hang though. Can you share your > > > > > > > > > > > > setup? > > > > > > > > > > > - config.txt: > > > > > > > > > > > > > > > > > > > > > > -------->8-------->8-------->8-------->8-------- > > > > > > > > > > > gpu_mem=16 > > > > > > > > > > > disable_splash=1 > > > > > > > > > > > > > > > > > > > > > > arm_64bit=1 > > > > > > > > > > > enable_uart=1 > > > > > > > > > > > uart_2ndstage=1 > > > > > > > > > > > > > > > > > > > > > > os_prefix=/u-boot/ > > > > > > > > > > > > > > > > > > > > > > [pi3] > > > > > > > > > > > force_turbo=1 > > > > > > > > > > > -------->8-------->8-------->8-------->8-------- > > > > > > > > > > > > > > > > > > > > > > - Raspberry Pi 3 Model B+ > > > > > > > > > > > - no HDMI connected > > > > > > > > > > Does it mean, the issue only occurs without HDMI connected? > > > > > > > > > > If you didn't test with HDMI yet, could you please do? > > > > > > > > > The error occurs with HDMI not connected, as vc4 is the gfx driver I > > > > > > > > > thought this might be of interest. :) > > > > > > > > > > > > > > > > > > I don't have a HDMI monitor here, but I'll come back to you as soon as I > > > > > > > > > get access to one (might take some time). > > > > > > > > It's not the first time an issue like this one would occur. I'm trying > > > > > > > > to make my Pi3 boot again, and will try to bisect the issue. > > > > > > > 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? > > > > > > No, I mean that, with vc4 as a module, 5.18 works but 5.19 doesn't, like > > > Marc said. But if vc4 is built in, both work. > > > > > > > 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) > > > > > > It felt like a clock or power domain issue to me indeed, but adding > > > clk_ignore_unused and pd_ignore_unused isn't enough, so it's probably > > > something a bit more complicated than just the clock / PD being > > > disabled. > > > > I found the offending patch: > > https://lore.kernel.org/dri-devel/20220225143534.405820-13-maxime@xxxxxxxxxx/ > > > > That code was removed because it was made irrelevant by that earlier patch: > > https://lore.kernel.org/dri-devel/20220225143534.405820-10-maxime@xxxxxxxxxx/ > > > > But it turns out that while it works when the driver is built-in, it > > doesn't when it's a module. If we add a clk_hw_get_rate() call right > > after that call to raspberrypi_fw_set_rate(), the rate returned is 0. > > > > I'm not entirely sure why, but I wonder if it's related to: > > https://github.com/raspberrypi/linux/issues/4962#issuecomment-1228593439 > > Turns out it's not, since the Pi3 is using the clk-bcm2835 driver. > > However, even reverting that patch fails. clk_set_min_rate fails because > the rate is protected, but it doesn't look like it is anywhere for that > clock, so I'm a bit confused. > > Even if we do remove the clock protection check in > clk_core_set_rate_nolock(), clk_calc_new_rates() will then fail because > the bcm2835 driver will round the clock rate below the minimum, which is > rejected. > > I'm not entirely sure what to do at this point. I guess the proper fix > would be to: > - Figure out why it's considered protected when it's not (or shouldn't be) Found out that one. The HSM clock has CLK_SET_RATE_GATE that will protect the rate for as long as the clock is enabled, so clk_prepare_enable / clk_set_min_rate doesn't work, but clk_set_min_rate / clk_prepare_enable does. Maxime
