[igt-dev] [PATCH i-g-t 10/11] lib/kms: Convert pipe id flags for a vblank using crtc offset

[Arkadiusz Hiler]

On Fri, Jul 17, 2020 at 06:43:59PM +0300, Khajapasha, Mohammed wrote:
> 
> 
> > -----Original Message-----
> > From: Hiler, Arkadiusz <arkadiusz.hiler at intel.com>
> > Sent: Friday, July 17, 2020 6:33 PM
> > To: Khajapasha, Mohammed <mohammed.khajapasha at intel.com>
> > Cc: igt-dev at lists.freedesktop.org
> > Subject: Re: [PATCH i-g-t 10/11] lib/kms: Convert pipe id flags for a vblank
> > using crtc offset
> >
> > On Sun, Jul 12, 2020 at 01:36:01AM +0530, Mohammed Khajapasha wrote:
> > > In i915 with non-contiguous pipes display, pipes always not same as
> > > crtc index in display pipes array. Hence reading pipe id flags for a
> > > vblank event using crtc offset.
> >
> > Mention in the commit message that crtc_offset was chosen because
> > crtc_index is too close to crtc_id which can cause confusion.
> 
> As per my understanding crtc_index and crtc_id are different, crtc_id is DRM mode object id
> assigned by DRM for each drm object. And crtc_index & crtc_offset both are same for list
> crtc in mode config list.

Yes, you are correct. IMO crtc_offset is a better name than crtc_index.

Imagine having crtc_id and crtc_index sprinkled all throughout the code.
It's very easy to mistake one for the other.

It's harder to make a similar mistake with crtc_id and crtc_offset.

-- 
Cheers,
Arek