[PATCH] drm/i915/gvt: remove call trace in plane scaling handler

[Yuan, Hang]

Got it. Thank you for the explaining!

> -----Original Message-----
> From: intel-gvt-dev [mailto:intel-gvt-dev-bounces at lists.freedesktop.org] On
> Behalf Of He, Min
> Sent: Thursday, April 18, 2019 9:29 AM
> To: hang.yuan at linux.intel.com; intel-gvt-dev at lists.freedesktop.org
> Subject: RE: [PATCH] drm/i915/gvt: remove call trace in plane scaling handler
> 
> Henry,
> When guest is trying to use the plane scaler, it will write to the PS_CTRL
> register on every plane update. And we don’t have mechanisms to notify the
> guest that scaler is not available. So if you modify it to gvt_vgpu_err(), it will
> cause massive dmesg logs in dom0, what's why we used WARN_ON_ONCE()
> to log it.
> 
> Thanks.
> 
> > -----Original Message-----
> > From: intel-gvt-dev
> > [mailto:intel-gvt-dev-bounces at lists.freedesktop.org] On Behalf Of
> > hang.yuan at linux.intel.com
> > Sent: Wednesday, April 17, 2019 6:41 PM
> > To: intel-gvt-dev at lists.freedesktop.org
> > Cc: Hang Yuan <hang.yuan at linux.intel.com>
> > Subject: [PATCH] drm/i915/gvt: remove call trace in plane scaling
> > handler
> >
> > From: Hang Yuan <hang.yuan at linux.intel.com>
> >
> > On guest MMIO access to scale a plane, print message but no call trace
> > dumped.
> >
> > Signed-off-by: Hang Yuan <hang.yuan at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/gvt/handlers.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gvt/handlers.c
> > b/drivers/gpu/drm/i915/gvt/handlers.c
> > index 18f01ee..d3d6788 100644
> > --- a/drivers/gpu/drm/i915/gvt/handlers.c
> > +++ b/drivers/gpu/drm/i915/gvt/handlers.c
> > @@ -1298,8 +1298,7 @@ static int pf_write(struct intel_vgpu *vgpu,
> >  	if ((offset == _PS_1A_CTRL || offset == _PS_2A_CTRL ||
> >  	   offset == _PS_1B_CTRL || offset == _PS_2B_CTRL ||
> >  	   offset == _PS_1C_CTRL) && (val & PS_PLANE_SEL_MASK) != 0) {
> > -		WARN_ONCE(true, "VM(%d): guest is trying to scaling a
> > plane\n",
> > -			  vgpu->id);
> > +		gvt_vgpu_err("unsupported display plane scaling
> > operation\n");
> >  		return 0;
> >  	}
> >
> > --
> > 2.7.4
> >
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