Re: 答复: 答复: [PATCH] drm/amdgpu: adjust gtt memory size

[Christian König]

Am 21.07.2016 um 13:15 schrieb Wang, Qingqing:
>
> Actually that discussion was held long ago internally but we never got 
> a conclusion on this IIRC. So we should probably continue the 
> discussion on this thread now.
>
> -there is a thread for this topic yesterday, some people are not in 
> amd-gfx mail list, we'd better discuss in the internal thread.
>
No, exactly for this reason we have the public mailing list. I for 
example wasn't part of the internal thread either.

Christian.

> ------------------------------------------------------------------------
> *发件人:* Christian König <deathsimple at vodafone.de>
> *发送时间:* 2016年7月21日 17:48:41
> *收件人:* Wang, Qingqing; amd-gfx at lists.freedesktop.org
> *主题:* Re: 答复: [PATCH] drm/amdgpu: adjust gtt memory size
> Am 21.07.2016 um 11:16 schrieb Wang, Qingqing:
>>
>> This doesn't work on 32bit systems since totalram is a long (IIRC) and
>> so this will certainly overflow.
>>
>> -- can you be more specific, how could the overflow happen?
>>
>
> Both values are 32bit on a 32bit system, so as soon as you have more 
> than 4GB installed this will overflow.
>
> You need to cast the long to a 64bit value to avoid that.
>
>>
>> Additional if I remember correctly we didn't ended the discussion on
>> what to do here with a conclusion.
>>
>> -- ok, since it happens in anther mail list, we should stop talking 
>> about it here, you can send out your ideas there.
>>
>
> Actually that discussion was held long ago internally but we never got 
> a conclusion on this IIRC. So we should probably continue the 
> discussion on this thread now.
>
> Regards,
> Christian.
>
>> ------------------------------------------------------------------------
>> *发件人:* amd-gfx <amd-gfx-bounces at lists.freedesktop.org> 代表 Christian 
>> König <deathsimple at vodafone.de>
>> *发送时间:* 2016年7月21日 16:53:05
>> *收件人:* Wang, Qingqing; amd-gfx at lists.freedesktop.org
>> *主题:* Re: [PATCH] drm/amdgpu: adjust gtt memory size
>> Am 21.07.2016 um 09:46 schrieb Ken Wang:
>> > Change-Id: If00d5b97ba9e30f9b7f68fdfc134a0f8b3ad2add
>> > Signed-off-by: Ken Wang <Qingqing.Wang at amd.com>
>> > ---
>> >   drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 7 ++++++-
>> >   drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 7 ++++++-
>> >   2 files changed, 12 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c 
>> b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>> > index a3b6048..0b095d5 100644
>> > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>> > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
>> > @@ -336,6 +336,11 @@ static int gmc_v7_0_mc_init(struct 
>> amdgpu_device *adev)
>> >   {
>> >        u32 tmp;
>> >        int chansize, numchan;
>> > +     u64 sysmem_size;
>> > +     struct sysinfo si;
>> > +
>> > +     si_meminfo(&si);
>> > +     sysmem_size = si.totalram * si.mem_unit;
>>
>> This doesn't work on 32bit systems since totalram is a long (IIRC) and
>> so this will certainly overflow.
>>
>> Additional if I remember correctly we didn't ended the discussion on
>> what to do here with a conclusion.
>>
>> Regards,
>> Christian.
>>
>> >
>> >        /* Get VRAM informations */
>> >        tmp = RREG32(mmMC_ARB_RAMCFG);
>> > @@ -392,7 +397,7 @@ static int gmc_v7_0_mc_init(struct 
>> amdgpu_device *adev)
>> >         * size equal to the 1024 or vram, whichever is larger.
>> >         */
>> >        if (amdgpu_gart_size == -1)
>> > -             adev->mc.gtt_size = max((1024ULL << 20), 
>> adev->mc.mc_vram_size);
>> > +             adev->mc.gtt_size = max((1024ULL << 20), 
>> min(adev->mc.mc_vram_size, sysmem_size/2));
>> >        else
>> >                adev->mc.gtt_size = (uint64_t)amdgpu_gart_size << 20;
>> >
>> > diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c 
>> b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>> > index 02b6872..790bf7a 100644
>> > --- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>> > +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
>> > @@ -413,6 +413,11 @@ static int gmc_v8_0_mc_init(struct 
>> amdgpu_device *adev)
>> >   {
>> >        u32 tmp;
>> >        int chansize, numchan;
>> > +     u64 sysmem_size;
>> > +     struct sysinfo si;
>> > +
>> > +     si_meminfo(&si);
>> > +     sysmem_size = si.totalram * si.mem_unit;
>> >
>> >        /* Get VRAM informations */
>> >        tmp = RREG32(mmMC_ARB_RAMCFG);
>> > @@ -469,7 +474,7 @@ static int gmc_v8_0_mc_init(struct 
>> amdgpu_device *adev)
>> >         * size equal to the 1024 or vram, whichever is larger.
>> >         */
>> >        if (amdgpu_gart_size == -1)
>> > -             adev->mc.gtt_size = max((1024ULL << 20), 
>> adev->mc.mc_vram_size);
>> > +             adev->mc.gtt_size = max((1024ULL << 20), 
>> min(adev->mc.mc_vram_size, sysmem_size/2));
>> >        else
>> >                adev->mc.gtt_size = (uint64_t)amdgpu_gart_size << 20;
>> >
>>
>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>
>

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