Re: 答复: 答复: [PATCH] drm/amdgpu:fix amdgpu_sa_bo_new error

Christian König deathsimple at
Wed Feb 8 15:59:10 UTC 2017

Am 08.02.2017 um 16:53 schrieb Liu, Monk:
> agreed, why not just use cpu to clear it ? is it because performance ?

Pixel Ding removed the CPU clear because "There's a failure caused by 
this is that handshaking gets timeout of SRIOV virtual function."

I can only assume that this is really adding to much delay at bootup.

> ------------------------------------------------------------------------
> *发件人:* Michel Dänzer <michel at>
> *发送时间:* 2017年2月8日 23:52:02
> *收件人:* Christian König; Liu, Monk
> *抄送:* amd-gfx at
> *主题:* Re: 答复: [PATCH] drm/amdgpu:fix amdgpu_sa_bo_new error
> On 09/02/17 12:30 AM, Christian König wrote:
> > The IB test make the decision if the hardware is working or not.
> >
> > So they should be the first commands (except for the ring tests) we send
> > to the hardware.
> >
> > When we allocate the fb before the test we send the clear command to the
> > hardware without knowing if the hardware really works or not.
> >
> > Not a big issue, but I think the order makes more sense that way.
> I just wonder if it's worth all the trouble, just to clear the fbcon
> buffer[0], if the result is that the console output is delayed, possibly
> indefinitely.

Actually that change is quite beneficial because the IB tests where 
usually revealing any problem.

Not 100% sure, but when we initialize the fb later that might actually 
allow us to better track such problems down.

Going to check that,

> [0] We don't have any other hardware acceleration for fbcon, so its BO
> is only accessed by the CPU and display hardware after this, and has to
> be pinned in the CPU visible area of VRAM at all times anyway.
> -- 
> Earthling Michel Dänzer               | 
> <>
> Libre software enthusiast             |             Mesa and X developer

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