Hi Stefan,
On Wed, Jun 29, 2022 at 10:50:21PM +0200, Stefan Wahren wrote:
> Hi Maxime,
>
> i tested todays drm-misc-next 9db35bb349 with Raspberry Pi 3 B Plus
> (arm/multi_v7_defconfig, mainline DTB) and get the following warning in the
> kernel logs:
>
> [ 25.698459] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
> [ 25.698657] ------------[ cut here ]------------
> [ 25.698660] WARNING: CPU: 1 PID: 153 at
> drivers/gpu/drm/vc4/vc4_hdmi_regs.h:487 vc4_hdmi_reset+0x3e0/0x4e0 [vc4]
> [ 25.698757] Modules linked in: brcmutil vc4(+) snd_soc_core ac97_bus
> sha256_generic libsha256 snd_pcm_dmaengine sha256_arm snd_pcm cfg80211
> snd_timer hci_uart btbcm snd soundcore bluetooth raspberrypi_hwmon
> drm_cma_helper ecdh_generic ecc libaes bcm2835_thermal microchip lan78xx
> crc32_arm_ce
> [ 25.698831] CPU: 1 PID: 153 Comm: systemd-udevd Not tainted
> 5.19.0-rc2-00085-g9db35bb349a0 #2
> [ 25.698839] Hardware name: BCM2835
> [ 25.698850] unwind_backtrace from show_stack+0x10/0x14
> [ 25.698866] show_stack from dump_stack_lvl+0x40/0x4c
> [ 25.698879] dump_stack_lvl from __warn+0xcc/0x144
> [ 25.698890] __warn from warn_slowpath_fmt+0x5c/0xb4
> [ 25.698900] warn_slowpath_fmt from vc4_hdmi_reset+0x3e0/0x4e0 [vc4]
> [ 25.698996] vc4_hdmi_reset [vc4] from vc4_hdmi_runtime_resume+0x4c/0x64
> [vc4]
> [ 25.699165] vc4_hdmi_runtime_resume [vc4] from vc4_hdmi_bind+0x208/0x994
> [vc4]
> [ 25.699333] vc4_hdmi_bind [vc4] from component_bind_all+0x100/0x230
> [ 25.699428] component_bind_all from vc4_drm_bind+0x1a8/0x280 [vc4]
> [ 25.699518] vc4_drm_bind [vc4] from
> try_to_bring_up_aggregate_device+0x160/0x1bc
> [ 25.699610] try_to_bring_up_aggregate_device from
> component_master_add_with_match+0xc4/0xf8
> [ 25.699622] component_master_add_with_match from
> vc4_platform_drm_probe+0xa0/0xc0 [vc4]
> [ 25.699712] vc4_platform_drm_probe [vc4] from platform_probe+0x5c/0xbc
> [ 25.699802] platform_probe from really_probe.part.0+0x9c/0x2b0
> [ 25.699812] really_probe.part.0 from __driver_probe_device+0xa8/0x13c
> [ 25.699823] __driver_probe_device from driver_probe_device+0x34/0x108
> [ 25.699834] driver_probe_device from __driver_attach+0xb4/0x17c
> [ 25.699846] __driver_attach from bus_for_each_dev+0x70/0xb0
> [ 25.699856] bus_for_each_dev from bus_add_driver+0x164/0x1f0
> [ 25.699867] bus_add_driver from driver_register+0x88/0x11c
> [ 25.699878] driver_register from do_one_initcall+0x40/0x1d4
> [ 25.699890] do_one_initcall from do_init_module+0x44/0x1d4
> [ 25.699901] do_init_module from sys_finit_module+0xbc/0xf8
> [ 25.699909] sys_finit_module from __sys_trace_return+0x0/0x10
> [ 25.699918] Exception stack(0xf568dfa8 to 0xf568dff0)
> [ 25.699926] dfa0: 6a09f700 00000000 00000016 b6dee8e0
> 00000000 b6def3f4
> [ 25.699934] dfc0: 6a09f700 00000000 00000000 0000017b 0053b9a8 0052a1dc
> 0053af10 00000000
> [ 25.699940] dfe0: be8e5160 be8e5150 b6de59d8 b6ed5ae0
> [ 25.699944] ---[ end trace 0000000000000000 ]---
>
> I was able to bisect the warning to the following commit:
>
> drm/vc4: hdmi: Move HDMI reset to pm_resume
>
> The BCM2835-37 found in the RaspberryPi 0 to 3 have a power domain
> attached to the HDMI block, handled in Linux through runtime_pm.
>
> That power domain is shared with the VEC block, so even if we put our
> runtime_pm reference in the HDMI driver it would keep being on. If the
> VEC is disabled though, the power domain would be disabled and we would
> lose any initialization done in our bind implementation.
>
> That initialization involves calling the reset function and initializing
> the CEC registers.
>
> Let's move the initialization to our runtime_resume implementation so
> that we initialize everything properly if we ever need to.
>
> Fixes: c86b41214362 ("drm/vc4: hdmi: Move the HSM clock enable to
> runtime_pm")
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20220613144800.326124-24-maxime@xxxxxxxxxx
> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
Yeah, I noticed it yesterday
https://lore.kernel.org/dri-devel/20220629123510.1915022-1-maxime@xxxxxxxxxx/T/#m1027cef33d8c66a302b2b8a80bab8a9dc6652f04
and
https://lore.kernel.org/dri-devel/20220629123510.1915022-1-maxime@xxxxxxxxxx/T/#mc869819c66f7b3df8b31a320636a9172780a58e7
Should address it
Maxime
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