[Intel-gfx] [RFC 06/14] drm/i915: Disable vlank interrupt for disabling MIPI cmd mode

[Daniel Vetter]

On Fri, May 29, 2015 at 07:14:43PM +0200, Daniel Vetter wrote:
> On Fri, May 29, 2015 at 04:06:58PM +0530, Gaurav K Singh wrote:
> > vblank interrupt should be disabled before starting the disable
> > sequence for MIPI command mode. Otherwise when pipe is disabled
> > TE interurpt will be still handled and one memory write command
> > will be sent with pipe disabled. This makes the pipe hw to get
> > stuck and it doesn't recover in the next enable sequence causing
> > display blank out.
> > 
> > Signed-off-by: Yogesh Mohan Marimuthu <yogesh.mohan.marimuthu at intel.com>
> > Signed-off-by: Gaurav K Singh <gaurav.k.singh at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dsi.c |   14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> > index 04d8ce0..aeea289 100644
> > --- a/drivers/gpu/drm/i915/intel_dsi.c
> > +++ b/drivers/gpu/drm/i915/intel_dsi.c
> > @@ -513,11 +513,25 @@ static void intel_dsi_enable_nop(struct intel_encoder *encoder)
> >  
> >  static void intel_dsi_pre_disable(struct intel_encoder *encoder)
> >  {
> > +	struct drm_device *dev = encoder->base.dev;
> >  	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> > +	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
> > +	int pipe = intel_crtc->pipe;
> >  	enum port port;
> >  
> >  	DRM_DEBUG_KMS("\n");
> >  
> > +	if (is_cmd_mode(intel_dsi)) {
> > +		dev->driver->disable_vblank(dev, pipe);
> > +
> > +		/*
> > +		 * Make sure that the last frame is sent otherwise pipe can get
> > +		 * stuck. Currently providing delay time for ~2 vblanks
> > +		 * assuming 60fps.
> > +		 */
> > +		mdelay(40);
> > +	}
> 
> Nope. You need to move around the drm_vblank_off suitably, only that
> function correctly handles all the book-keeping around vblank interrupts.
> If this doesn't work out because of ordering we need to dig into this and
> figure out something. Worst case we need to push the drm_vblank_off call
> into encoder callbacks for everyone. That's something we already discussed
> but then decided against.

I seem to be blind, but where exactly is that vblank-driven upload code?
-Daniel

> -Daniel
> 
> > +
> >  	if (is_vid_mode(intel_dsi)) {
> >  		/* Send Shutdown command to the panel in LP mode */
> >  		for_each_dsi_port(port, intel_dsi->ports)
> > -- 
> > 1.7.9.5
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch