Re: 回复: Re: [PATCH] drm/amdgpu: fixup bad vram size on gmc v8

[Christian König]

Hi Zongmin,

that strongly sounds like the ASIC is not correctly initialized when 
trying to read the register.

What board and environment are you using this GPU with? Is that a normal 
x86 system?

Regards,
Christian.

Am 16.12.21 um 04:11 schrieb 周宗敏:
>
> 1.
>
>     the problematic boards that I have tested is [AMD/ATI] Lexa PRO
>     [Radeon RX 550/550X] ;  and the vbios version : 113-RXF9310-C09-BT
>
> 2.
>
>     When an exception occurs I can see the following changes in the
>     values of vram size get from RREG32(mmCONFIG_MEMSIZE) ,
>
>     it seems to have garbage in the upper 16 bits
>
>     image.png
>
>
> 3.
>
>     and then I can also see some dmesg like below:
>
>     when vram size register have garbage,we may see error message like
>     below:
>
>     amdgpu 0000:09:00.0: VRAM: 4286582784M 0x000000F400000000 -
>     0x000FF8F4FFFFFFFF (4286582784M used)
>
>     the correct message should like below:
>
>     amdgpu 0000:09:00.0: VRAM: 4096M 0x000000F400000000 -
>     0x000000F4FFFFFFFF (4096M used)
>
>
>     if you have any problems,please send me mail.
>
>     thanks very much.
>
>
> ----
>
> *主　题：*Re: [PATCH] drm/amdgpu: fixup bad vram size on gmc v8
> *日　期：*2021-12-16 04:23
> *发件人：*Alex Deucher
> *收件人：*Zongmin Zhou
>
>
> On Wed, Dec 15, 2021 at 10:31 AM Zongmin Zhouwrote:
> >
> > Some boards(like RX550) seem to have garbage in the upper
> > 16 bits of the vram size register.  Check for
> > this and clamp the size properly.  Fixes
> > boards reporting bogus amounts of vram.
> >
> > after add this patch,the maximum GPU VRAM size is 64GB,
> > otherwise only 64GB vram size will be used.
>
> Can you provide some examples of problematic boards and possibly a
> vbios image from the problematic board?  What values are you seeing?
> It would be nice to see what the boards are reporting and whether the
> lower 16 bits are actually correct or if it is some other issue.  This
> register is undefined until the asic has been initialized.  The vbios
> programs it as part of it's asic init sequence (either via vesa/gop or
> the OS driver).
>
> Alex
>
>
> >
> > Signed-off-by: Zongmin Zhou
> > ---
> >  drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 13 ++++++++++---
> >  1 file changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c 
> b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> > index 492ebed2915b..63b890f1e8af 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
> > @@ -515,10 +515,10 @@ static void gmc_v8_0_mc_program(struct 
> amdgpu_device *adev)
> >  static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
> >  {
> >         int r;
> > +       u32 tmp;
> >
> >         adev->gmc.vram_width = amdgpu_atombios_get_vram_width(adev);
> >         if (!adev->gmc.vram_width) {
> > -               u32 tmp;
> >                 int chansize, numchan;
> >
> >                 /* Get VRAM informations */
> > @@ -562,8 +562,15 @@ static int gmc_v8_0_mc_init(struct 
> amdgpu_device *adev)
> >                 adev->gmc.vram_width = numchan * chansize;
> >         }
> >         /* size in MB on si */
> > -       adev->gmc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL 
> * 1024ULL;
> > -       adev->gmc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) * 
> 1024ULL * 1024ULL;
> > +       tmp = RREG32(mmCONFIG_MEMSIZE);
> > +       /* some boards may have garbage in the upper 16 bits */
> > +       if (tmp & 0xffff0000) {
> > +               DRM_INFO("Probable bad vram size: 0x%08x\n", tmp);
> > +               if (tmp & 0xffff)
> > +                       tmp &= 0xffff;
> > +       }
> > +       adev->gmc.mc_vram_size = tmp * 1024ULL * 1024ULL;
> > +       adev->gmc.real_vram_size = adev->gmc.mc_vram_size;
> >
> >         if (!(adev->flags & AMD_IS_APU)) {
> >                 r = amdgpu_device_resize_fb_bar(adev);
> > --
> > 2.25.1
> >
> >
> > No virus found
> >                 Checked by Hillstone Network AntiVirus
>

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