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

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Message-ID: <bde48eef-4d8a-4cfa-b824-6de88c0f87fd@amd.com>
Date: Mon, 22 Apr 2024 14:59:36 +0200
From: Christian König <christian.koenig@....com>
To: Qiang Ma <maqianga@...ontech.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

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.

>
> 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);
>>