[Intel-gfx] [PATCH] drm/i915: suppress atomic commit error message under gvt-g env

[bing.niu]

Hi ville:
thanks for the reply. :)
yeah! we present a virtual monitor to guest associating with those 
vregs. however, we use remote display protocol like x11vnc to display 
vm's desktop.

cheer~

-----Original Message-----
From: Ville Syrjälä [mailto:ville.syrjala at linux.intel.com] Sent: Friday, 
March 03, 2017 7:53 PM
To: Niu, Bing <bing.niu at intel.com>
Cc: intel-gfx at lists.freedesktop.org; Lv, Zhiyuan <zhiyuan.lv at intel.com>
Subject: Re: [Intel-gfx] [PATCH] drm/i915: suppress atomic commit error 
message under gvt-g env

On Fri, Mar 03, 2017 at 06:53:08AM -0500, bing.niu at intel.com wrote:
> From: Bing Niu <bing.niu at intel.com>
>
> under virtualization enviroment, it is possible guest update pipe
> registers across vblank intervals due to overhead of mmio traps or vm
> schedule out. However, it is safe since those pipe update happen in
> virual registers and will not be committed to hardware.

Hmm. How are these virtual registers used? Do you present some kind of 
virtualized display for the guest? And if this stuff fails does that 
mean that guest will fail in doing atomic display updates?

> suppress that
> atomic commit error message under virtualization case to avoid
> confusing user.
>
> Signed-off-by: Bing Niu <bing.niu at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_sprite.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_sprite.c
> b/drivers/gpu/drm/i915/intel_sprite.c
> index b16a295..5ce1ec6 100644
> --- a/drivers/gpu/drm/i915/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/intel_sprite.c
> @@ -158,6 +158,7 @@ void intel_pipe_update_end(struct intel_crtc *crtc, struct intel_flip_work *work
>  	int scanline_end = intel_get_crtc_scanline(crtc);
>  	u32 end_vbl_count = intel_crtc_get_vblank_counter(crtc);
>  	ktime_t end_vbl_time = ktime_get();
> +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
>
>  	if (work) {
>  		work->flip_queued_vblank = end_vbl_count; @@ -184,7 +185,7 @@ void
> intel_pipe_update_end(struct intel_crtc *crtc, struct intel_flip_work *work
>  	local_irq_enable();
>

if (vgpu_active())
	return;

here might look neater, and would still work with the additional error 
print that Maarten is going to add [1]

[1] https://patchwork.freedesktop.org/patch/141260/

>  	if (crtc->debug.start_vbl_count &&
> -	    crtc->debug.start_vbl_count != end_vbl_count) {
> +	    crtc->debug.start_vbl_count != end_vbl_count &&
> +!intel_vgpu_active(dev_priv)) {
>  		DRM_ERROR("Atomic update failure on pipe %c (start=%u end=%u) time %lld us, min %d, max %d, scanline start %d, end %d\n",
>  			  pipe_name(pipe), crtc->debug.start_vbl_count,
>  			  end_vbl_count,
> --
> 2.7.4
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Ville Syrjälä
Intel OTC