deprecated register issues

[Deucher, Alexander]

Right.  We ran into issues with reading back that register at runtime when UMDs queried it when other stuff was in flight, so we just read it once at startup and cache the results. Now when UMDs request it, we return the cached value.


Alex

________________________________
From: Koenig, Christian
Sent: Wednesday, March 7, 2018 9:31:13 AM
To: Mao, David; Liu, Monk
Cc: Deucher, Alexander; amd-gfx at lists.freedesktop.org; Jin, Jian-Rong
Subject: Re: deprecated register issues

Hi David,

well I just figured that this is a misunderstanding.

Accessing this register and some other deprecated registers can cause problem when invalidating VMHUBs.

This register itself isn't deprecated, the wording in a patch fixing things is just a bit unclear.

Question is is that register still accessed regularly or is it value cached after startup?

Regards,
Christian.

Am 07.03.2018 um 15:25 schrieb Mao, David:
We requires base driver to provide the mask of disabled RB.
This is why kernel read the CC_RB_BACKEND_DISABLE to collect the harvest configuration.
Where did you get to know that the register is deprecated?
I think it should still be there.

Best Regards,
David

On Mar 7, 2018, at 9:49 PM, Liu, Monk <Monk.Liu at amd.com<mailto:Monk.Liu at amd.com>> wrote:

+ UMD guys

Hi David

Do you know if GC_USER_RB_BACKEND_DISABLE is still exist for gfx9/vega10 ?

We found CC_RB_BACKEND_DISABLE was deprecated but looks it is still in use in kmd, so
I want to check with you both of above registers

Thanks
/Monk

From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf Of Christian K?nig
Sent: 2018年3月7日 20:26
To: Liu, Monk <Monk.Liu at amd.com<mailto:Monk.Liu at amd.com>>; Deucher, Alexander <Alexander.Deucher at amd.com<mailto:Alexander.Deucher at amd.com>>
Cc: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>
Subject: Re: deprecated register issues

Hi Monk,

I honestly don't have the slightest idea why we are still accessing CC_RB_BACKEND_DISABLE. Maybe it still contains some useful values?

Key point was that we needed to stop accessing it all the time to avoid triggering problems.

Regards,
Christian.

Am 07.03.2018 um 13:11 schrieb Liu, Monk:

Hi Christian



I remember you and AlexD mentioned that a handful registers are deprecated for greenland (gfx9)

e.g. CC_RB_BACKEND_DISABLE



do you know why we still have this routine ?


static u32
gfx_v9_0_get_rb_active_bitmap(struct amdgpu_device *adev)

{

    u32 data, mask;



    data = RREG32_SOC15(GC,
0, mmCC_RB_BACKEND_DISABLE);

    data |= RREG32_SOC15(GC,
0, mmGC_USER_RB_BACKEND_DISABLE);



    data &= CC_RB_BACKEND_DISABLE__BACKEND_DISABLE_MASK;

    data >>= GC_USER_RB_BACKEND_DISABLE__BACKEND_DISABLE__SHIFT;



    mask = amdgpu_gfx_create_bitmask(adev->gfx.config.max_backends_per_se /

                     adev->gfx.config.max_sh_per_se);



    return (~data) & mask;

}



see that it still read CC_RB_BACKEND_DISABLE



thanks



/Monk






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