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Date: Mon, 22 Apr 2024 20:33:29 +0800
From: Qiang Ma <maqianga@uniontech.com>
To: Christian =?UTF-8?B?S8O2bmln?= <christian.koenig@amd.com>
Cc: alexander.deucher@amd.com, Xinhui.Pan@amd.com, airlied@gmail.com,
 daniel@ffwll.ch, srinivasan.shanmugam@amd.com,
 Arunpravin.PaneerSelvam@amd.com, le.ma@amd.com, Felix.Kuehling@amd.com,
 mukul.joshi@amd.com, amd-gfx@lists.freedesktop.org,
 dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/amdgpu: Fixup bad vram size on gmc v6 and v7
Message-ID: <D94775003178862D+20240422203329.49844e71@john-PC>
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	<68f02c5c-5591-4d6f-9926-b0fc6f9f6287@amd.com>
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On Mon, 22 Apr 2024 11:40:26 +0200
Christian K=C3=B6nig <christian.koenig@amd.com> wrote:

> Am 22.04.24 um 07:26 schrieb Qiang Ma:
> > Some boards(like Oland PRO: 0x1002:0x6613) seem to have
> > garbage in the upper 16 bits of the vram size register,
> > kern log as follows:
> >
> > [    6.000000] [drm] Detected VRAM RAM=3D2256537600M, BAR=3D256M
> > [    6.007812] [drm] RAM width 64bits GDDR5
> > [    6.031250] [drm] amdgpu: 2256537600M of VRAM memory ready
> >
> > This is obviously not true, check for this and clamp the size
> > properly. Fixes boards reporting bogus amounts of vram,
> > kern log as follows:
> >
> > [    2.789062] [drm] Probable bad vram size: 0x86800800
> > [    2.789062] [drm] Detected VRAM RAM=3D2048M, BAR=3D256M
> > [    2.789062] [drm] RAM width 64bits GDDR5
> > [    2.789062] [drm] amdgpu: 2048M of VRAM memory ready =20
>=20
> Well we had patches like this one here before and so far we always=20
> rejected them.
>=20
> When the mmCONFIG_MEMSIZE register isn't properly initialized then
> there is something wrong with your hardware.
>=20
> Working around that in the software driver is not going to fly.
>=20
> Regards,
> Christian.
>=20
Hi Christian:
I see that two patches for this issue have been merged, and the
patches are as follows:

11544d77e397 drm/amdgpu: fixup bad vram size on gmc v8
0ca223b029a2 drm/radeon: fixup bad vram size on SI

Qiang Ma

> > Signed-off-by: Qiang Ma <maqianga@uniontech.com>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c | 11 +++++++++--
> >   drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 13 ++++++++++---
> >   2 files changed, 19 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
> > b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c index
> > 23b478639921..3703695f7789 100644 ---
> > a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c +++
> > b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c @@ -309,8 +309,15 @@ static
> > int gmc_v6_0_mc_init(struct amdgpu_device *adev) }
> >   	adev->gmc.vram_width =3D numchan * chansize;
> >   	/* size in MB on si */
> > -	adev->gmc.mc_vram_size =3D RREG32(mmCONFIG_MEMSIZE) *
> > 1024ULL * 1024ULL;
> > -	adev->gmc.real_vram_size =3D RREG32(mmCONFIG_MEMSIZE) *
> > 1024ULL * 1024ULL;
> > +	tmp =3D 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 &=3D 0xffff;
> > +	}
> > +	adev->gmc.mc_vram_size =3D tmp * 1024ULL * 1024ULL;
> > +	adev->gmc.real_vram_size =3D adev->gmc.mc_vram_size;
> >  =20
> >   	if (!(adev->flags & AMD_IS_APU)) {
> >   		r =3D amdgpu_device_resize_fb_bar(adev);
> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> > b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c index
> > 3da7b6a2b00d..1df1fc578ff6 100644 ---
> > a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c +++
> > b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c @@ -316,10 +316,10 @@
> > static void gmc_v7_0_mc_program(struct amdgpu_device *adev) static
> > int gmc_v7_0_mc_init(struct amdgpu_device *adev) {
> >   	int r;
> > +	u32 tmp;
> >  =20
> >   	adev->gmc.vram_width =3D
> > amdgpu_atombios_get_vram_width(adev); if (!adev->gmc.vram_width) {
> > -		u32 tmp;
> >   		int chansize, numchan;
> >  =20
> >   		/* Get VRAM informations */
> > @@ -363,8 +363,15 @@ static int gmc_v7_0_mc_init(struct
> > amdgpu_device *adev) adev->gmc.vram_width =3D numchan * chansize;
> >   	}
> >   	/* size in MB on si */
> > -	adev->gmc.mc_vram_size =3D RREG32(mmCONFIG_MEMSIZE) *
> > 1024ULL * 1024ULL;
> > -	adev->gmc.real_vram_size =3D RREG32(mmCONFIG_MEMSIZE) *
> > 1024ULL * 1024ULL;
> > +	tmp =3D 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 &=3D 0xffff;
> > +	}
> > +	adev->gmc.mc_vram_size =3D tmp * 1024ULL * 1024ULL;
> > +	adev->gmc.real_vram_size =3D adev->gmc.mc_vram_size;
> >  =20
> >   	if (!(adev->flags & AMD_IS_APU)) {
> >   		r =3D amdgpu_device_resize_fb_bar(adev); =20
>=20
>=20