On Tue, Sep 05, 2017 at 09:27:47AM +0000, Shankar, Uma wrote: > > > >-----Original Message----- > >From: Kahola, Mika > >Sent: Tuesday, September 5, 2017 2:03 PM > >To: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > >Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Shankar, Uma <uma.shankar@xxxxxxxxx> > >Subject: Re: [PATCH 1/2] drm/i915/dsi: Send SHUTDOWN only for v3+ > >VBT's > > > >On Mon, 2017-09-04 at 18:04 +0300, Ville Syrjälä wrote: > >> On Mon, Sep 04, 2017 at 10:59:32AM +0300, Mika Kahola wrote: > >> > > >> > On Fri, 2017-09-01 at 16:43 +0300, Ville Syrjälä wrote: > >> > > > >> > > On Fri, Sep 01, 2017 at 10:51:00AM +0300, Mika Kahola wrote: > >> > > > > >> > > > > >> > > > According to spec we should send SHUTDOWN before > >> > > > MIPI_SEQ_DISPLAY_OFF for > >> > > > v3+ VBT's. Testing with VBT v3 the current implementation > >> > > > yields > >> > > > the > >> > > > following error message > >> > > > > >> > > > *ERROR* Video mode command 0x00000041 send failed. > >> > > > > >> > > > To get rid of this error message, let's limit SHUTDOWN only for > >> > > > VBT versions 3 or higher. > >> > > In the patch you limit it to version 4+, which doesn't make sense > >> > > since AFAIK there is no version 4 of the sequence block. > >> > It seems that sending SHUTDOWN signal doesn't make any sense either. > >> > Whenever we send that signal it just causes this error message. Do > >> > we really need to signal this? From functionality point of view > >> > there's no difference. > >> Well, the spec doesn't even explain what this "shut down" command > >> does. > >> Is it actually the DCS "display off" command, or something else? > >It seems to do something. At least the intel_wait_for_register() times out when > >sending SHUTDOWN signal. Maybe it just shuts down display so we can't even > >read the registers after that. > > > >This brings me to another idea. Maybe we should skip > >intel_wait_for_register() if we have sent out SHUTDOWN signal? > > > >> > >> Did you try reverting bbdf0b2ff32a ("drm/i915/bxt: Disable device > >> ready before shutdown command")? That looks suspicious to me. But so > >> does about half of the DSI code since it never seems to follow the > >> spec, and we end up doing totally different things on different > >> platforms without any explanation why that is). > >I haven't tried that. I will give it a go and see what happens. > > > > The issue is happening due to Device Ready setting. It was added to resolve a DSI split screen > issue in dual link DSI panels. Since DSI dual link is not enabled and will require a bit of work in > upstream, we should revert this change. Vidya will send the change and also work on enabling > dual link support in upstream. > > FYI - SHUTDOWN is a short packet peripheral command that turns off the display in a Video Mode > display module for power saving. There is no SHUTDOWN comamnd in the DCS spec that I can find. > > For DSI, there have been issues with different panels requiring some unconventional changes, and also bspec > sometimes doesn't cover everything generically. So, it gets a bit challenging :( > > Regards, > Uma Shankar > > >> > > >> > > >> > > > >> > > > >> > > > > >> > > > > >> > > > > >> > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102404 > >> > > > Signed-off-by: Mika Kahola <mika.kahola@xxxxxxxxx> > >> > > > --- > >> > > > drivers/gpu/drm/i915/intel_dsi.c | 2 +- > >> > > > 1 file changed, 1 insertion(+), 1 deletion(-) > >> > > > > >> > > > diff --git a/drivers/gpu/drm/i915/intel_dsi.c > >> > > > b/drivers/gpu/drm/i915/intel_dsi.c > >> > > > index 2a0f5d3..b48b9b7 100644 > >> > > > --- a/drivers/gpu/drm/i915/intel_dsi.c > >> > > > +++ b/drivers/gpu/drm/i915/intel_dsi.c > >> > > > @@ -916,7 +916,7 @@ static void intel_dsi_disable(struct > >> > > > intel_encoder *encoder, > >> > > > * MIPI_SEQ_DISPLAY_OFF only for v3+ VBTs, but field testing > >> > > > * has shown that the v3 sequence works for v2 VBTs too > >> > > > */ > >> > > > - if (is_vid_mode(intel_dsi)) { > >> > > > + if (is_vid_mode(intel_dsi) && dev_priv- > >> > > > > > >> > > > > vbt.dsi.seq_version > 3) { > >> > > > /* Send Shutdown command to the panel in LP mode */ > >> > > > for_each_dsi_port(port, intel_dsi->ports) > >> > > > dpi_send_cmd(intel_dsi, SHUTDOWN, false, port); > >> > > > -- > >> > > > 2.7.4 > >> > > > > >> > > > _______________________________________________ > >> > > > Intel-gfx mailing list > >> > > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > >> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx > >> > -- > >> > Mika Kahola - Intel OTC > >-- > >Mika Kahola - Intel OTC > -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx