FreeBSD / amdgpu / Vega 3, pstate TEST_DEBUG_DATA: 0x0

[Harry Wentland]

On 2020-04-24 8:34 a.m., Andriy Gapon wrote:
> 
> First, I understand that my platform is not directly supported and probably not
> very interesting, but I still hope to get some tips or pointers.
> 

Hi Andriy,

yeah, limited insight here since FreeBSD isn't something I'm familiar
with. :)

> I am trying to get amdgpu/FreeBSD going on Motile M141 laptop with Ryzen 3 3200U
> CPU that has Vega 3 graphics integrated.  When amdgpu starts loading the screen
> goes black and never lights up again.  I am not sure whether there is no signal
> at all or whether the backlight is turned off, but the screen is completely
> dark.  I can blindly interact with the system, so it's not crashed or hung.
> From system logs I can see that the driver attaches successfully.  It recognizes
> the hardware, loads its firmware, detects the eDP screen and so on.
> 

Does BSD have a way to check or set your backlight value manually (a la
/sys/class/backlight on linux)? If so I'd suggest checking and setting
it to non-zero values, ideally to max_brightness.

Have you tried an external display?

> The FreeBSD's amdgpu port that I am trying is based on code circa 5.0.
> There is no newer version ported.
> I tried a couple of Linux distros with 5.3.x kernels and they worked without any
> problems. So that gives me some hope.
> 
> I compared driver messages (with drm_debug set to 0xfff) between Linux and
> FreeBSD and they look quite similar.  Except for one thing.
> In the FreeBSD case there are these error messages that are not seen with Linux:
> 
> [drm] pstate TEST_DEBUG_DATA: 0x0
> WARNING !(0) failed at
> /usr/home/avg/devel/kms-drm/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c:868
> #0 0xffffffff83451633 at linux_dump_stack+0x23
> #1 0xffffffff8325a9ee at dcn10_verify_allow_pstate_change_high+0x4e
> #2 0xffffffff8325e925 at dcn10_wait_for_mpcc_disconnect+0x25
> #3 0xffffffff8325de53 at dcn10_disable_plane+0x53
> #4 0xffffffff8325c9f5 at dcn10_init_hw+0x755
> #5 0xffffffff83295ca8 at dc_create+0x538
> #6 0xffffffff8327a8da at dm_hw_init+0x1ea
> #7 0xffffffff831701d1 at amdgpu_device_init+0x1b11
> #8 0xffffffff83185177 at amdgpu_driver_load_kms+0xd7
> #9 0xffffffff833f138e at drm_dev_register+0x17e
> #10 0xffffffff83178dea at amdgpu_pci_probe+0x18a
> #11 0xffffffff83456f40 at linux_pci_attach+0x560
> #12 0xffffffff80bf68ea at device_attach+0x3ca
> #13 0xffffffff80bf6490 at device_probe_and_attach+0x70
> #14 0xffffffff80bf8358 at bus_generic_driver_added+0x58
> #15 0xffffffff80bf4289 at devclass_driver_added+0x39
> #16 0xffffffff80bf41c7 at devclass_add_driver+0x147
> #17 0xffffffff83455ae9 at _linux_pci_register_driver+0xc9
> 
> That warning plus stack trace is actually BREAK_TO_DEBUGGER() in the original
> Linux code.
> So, that makes me think that the problem is pretty serious.

BREAK_TO_DEBUGGER is probably overly scary here. It's somewhat a concern
as this means power consumption might be higher than expected. We've
seen this issue on several systems without any other adverse effects to
usability.

Harry

> I tried searching for "TEST_DEBUG_DATA: 0x0" and I could not find a single
> result with "0x0" in it.  Usually there is some non-zero value.
> To me this looks like maybe some hardware component is not turned on...
> Perhaps this is something relatively obvious for people that hack on the driver
> and the hardware.
> I hope to receive some hint about what to look for.
> I can cherry-pick commits from Linux, apply patches, add additional debugging
> logs, etc.
> 
> FreeBSD amdgpu dmesg: https://people.freebsd.org/~avg/amdgpu.dmesg.txt
> Full Linux dmesg: https://people.freebsd.org/~avg/linux-5.3.0-28.dmesg.out
> 
> And with with drm_debug=0xfff.
> FreeBSD: https://people.freebsd.org/~avg/fbsd-dmesg.txt
> Linux: https://people.freebsd.org/~avg/linux-5.3.9-dmesg.txt
> 
> I see that both Linux and FreeBSD have similar messages about failing to load
> some microcode components, but I guess that it must be okay since Linux works:
> [    4.487381] [drm] reserve 0x400000 from 0xf400c00000 for PSP TMR
> [    4.564893] [drm] failed to load ucode id (12)
> [    4.564894] [drm] psp command failed and response status is (-53233)
> [    4.567891] [drm] failed to load ucode id (13)
> [    4.567892] [drm] psp command failed and response status is (-65521)
> [    4.570891] [drm] failed to load ucode id (14)
> [    4.570892] [drm] psp command failed and response status is (-65521)
> 
> Thank you!
>