linux-kernel - Re: [PATCH] drm/amdgpu: Fixup bad vram size on gmc v6 and v7

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Message-ID: <2778C515DE59A537+20240422214447.231a09de@john-PC>
Date: Mon, 22 Apr 2024 21:44:47 +0800
From: Qiang Ma <maqianga@...ontech.com>
To: Christian König <christian.koenig@....com>
Cc: alexander.deucher@....com, Xinhui.Pan@....com, airlied@...il.com,
 daniel@...ll.ch, srinivasan.shanmugam@....com,
 Arunpravin.PaneerSelvam@....com, le.ma@....com, Felix.Kuehling@....com,
 mukul.joshi@....com, amd-gfx@...ts.freedesktop.org,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/amdgpu: Fixup bad vram size on gmc v6 and v7

On Mon, 22 Apr 2024 14:59:36 +0200
Christian König <christian.koenig@....com> wrote:

> Am 22.04.24 um 14:33 schrieb Qiang Ma:
> > On Mon, 22 Apr 2024 11:40:26 +0200
> > Christian König <christian.koenig@....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=2256537600M, BAR=256M
> >>> [    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=2048M, BAR=256M
> >>> [    2.789062] [drm] RAM width 64bits GDDR5
> >>> [    2.789062] [drm] amdgpu: 2048M of VRAM memory ready  
> >> Well we had patches like this one here before and so far we always
> >> rejected them.
> >>
> >> When the mmCONFIG_MEMSIZE register isn't properly initialized then
> >> there is something wrong with your hardware.
> >>
> >> Working around that in the software driver is not going to fly.
> >>
> >> Regards,
> >> Christian.
> >>  
> > 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  
> 
> Mhm, I remember that we discussed reverting those but it looks like
> that never happened. I need to ask around internally.
> 
> Question is do you see any other problems with the board? E.g.
> incorrect connector or harvesting configuration?
> 
> Regards,
> Christian.
> 

At present, no other problems have been found.
Configured as radeon driver, display is normal. 
But this problem is found when I switch to amdgpu driver, and the
startup fails with black screen.
After add the patch, the startup was successful, display is normal.

Qiang Ma

> >
> > Qiang Ma
> >  
> >>> Signed-off-by: Qiang Ma <maqianga@...ontech.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 = 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);
> >>> 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;
> >>>    
> >>>    	adev->gmc.vram_width =
> >>> amdgpu_atombios_get_vram_width(adev); if (!adev->gmc.vram_width) {
> >>> -		u32 tmp;
> >>>    		int chansize, numchan;
> >>>    
> >>>    		/* Get VRAM informations */
> >>> @@ -363,8 +363,15 @@ static int gmc_v7_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);  
> >>  
> 
>