Re: [igt-dev] [PATCH i-g-t 3/3] kms/test: Pass correct pipe value to print pipe name

Khajapasha, Mohammed
2020-03-17T05:11:32Z

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Sent: Tuesday, March 10, 2020 5:45 PM
> To: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Khajapasha, Mohammed <mohammed.khajapasha@intel.com>; igt-
> dev@lists.freedesktop.org
> Subject: Re: [igt-dev] [PATCH i-g-t 3/3] kms/test: Pass correct pipe value to
> print pipe name
>
> On Tue, Mar 10, 2020 at 10:20:33AM +0200, Jani Nikula wrote:
> > On Tue, 10 Mar 2020, "Khajapasha, Mohammed"
> <mohammed.khajapasha@intel.com> wrote:
> > > Are you saying, we should get rid of pipe enum and make it array
> > > index based? Is my understanding correct? At present, every IGT
> > > subtest iterates over pipe list using "enum pipe" and this is
> > > getting passed down.
> >
> > I am saying do not conflate enum pipe and crtc index.
> >
> > If you call something a pipe, it should be the pipe, not crtc index.
> > And vice versa.
> >
> > It gets really confusing really quick if you call something a pipe,
> > and then go on to convert it into a pipe, as if it wasn't a pipe already.
> >
> > In i915 we've removed all assumptions that pipe == crtc index. So
> > should igt.
>
> I tend to agree, especially as other hw doens't use the "pipe"
> terminology, nor do they necessarily refer to them with A/B/C/...
>
> The ugly part would be that we'd have maybe rename all tests with a pipe
> in the name. Should we just use the crtc index as a bare number in those
> cases?

As per my understandings, yes, we need to use bare number of crtc index
to get the pipe in display->pipes[] array for for_each_pipe() macros.

>
> This would also have some complications for being able to quickly see
> which pipe had a specific failure as you have to dig through the logs to get
> that (though we'd anyway need to do that if the pipes are fused off in a
> way that makes the crtc index not match the pipe).
>
> Also in some cases we may actually want to know which pipe we're dealing
> with, but currently there is no convenient way for userspace to find out
> which pipe maps to which crtc.
>
In this patch series, we are able to map the kernel pipe to IGT pipe using
GET_PIPE_FROM_CRTC_ID ioctl, with this we are able to print the logs for failure
pipes in IGT.

> --
> Ville Syrjälä
> Intel