On Tue, 06 Dec 2016, Daniel Vetter <daniel@xxxxxxxx> wrote: > On Mon, Dec 05, 2016 at 06:11:44PM +0100, Thierry Reding wrote: >> On Mon, Dec 05, 2016 at 05:21:24PM +0100, Daniel Vetter wrote: >> > On Mon, Dec 05, 2016 at 12:11:46PM +0100, Thierry Reding wrote: >> > > On Mon, Dec 05, 2016 at 09:16:27AM +0100, Daniel Vetter wrote: >> > > > On Mon, Dec 05, 2016 at 08:57:43AM +0100, Thierry Reding wrote: >> > > > > On Sat, Dec 03, 2016 at 04:35:24AM +0000, Sharma, Shashank wrote: >> > > > > > Hi Thierry, >> > > > > > >> > > > > > If you can please have a look on this patch, I had written one to parse HF-VSDB, which was covering SCDC detection too. >> > > > > > https://patchwork.kernel.org/patch/9452259/ >> > > > > >> > > > > I think there had been pushback before about caching capabilities from >> > > > > EDID, so from that point of view my patch is more inline with existing >> > > > > EDID parsing API. >> > > > >> > > > Hm, where was that pushback? We do have a bit a mess between explicitly >> > > > parsing stuff (e.g. eld) and stuffing parsed data into drm_display_info. >> > > >> > > You did object to a very similar patch some time ago that did a similar >> > > thing for DPCD stuff. And also Villa had commented on an earlier patch >> > > from Jose about concerns of bloating core structures: >> > > >> > > https://patchwork.freedesktop.org/patch/104806/ >> > >> > DPCD I complained about because somehow we ended up with 2 sets of >> > helpers, one filling a struct and the others returning directly. I >> > objected to the fact that there's 2 (and imo your patch duplicated even >> > more), not that I think one approach is clearly inferior to the other. >> >> My recollection is that I had proposed that I do the work of >> transitioning users of the parsers to the cached information but you had >> said that it wasn't worth the churn and that we should just go with the >> existing scheme of passing around the DPCD buffer and extending the >> parsers as necessary. > > Hm, I guess it wasn't clear to me that you've offered to do all the > conversions. Doing that would be awesome I think (but quite a bit of > work), and if we bother with it, parsing into a struct is imo the better > idea long-term. I'm concerned about invalidating the data in the structs at the right times. We keep having issues with that whenever we cache stuff. BR, Jani. > >> From that I inferred that the same would be true for EDID and since we >> already have a couple of helpers that operate on struct edid * and which >> return features, continuing that scheme was preferred. >> >> Anyway, I don't really care either way. Maybe you and Ville can duke it >> out whether or not we want all of the fields parsed, irrespective of >> whether or not they will be used. Then I'll go with whatever you decide. >> >> > Demanding that there's some real users is also a valid point. >> > >> > > > I think long-term stuffing it into drm_display_info is probably better, >> > > > since then we only have 1 interaction point between the probe code and the >> > > > atomic_check code. That should be useful for eventually fixing the lack of >> > > > locking between the two, if I ever get around to that ;-) >> > > >> > > I don't really have objections to caching the results of parsing, it's >> > > what I had proposed and what seemed most natural back when I was working >> > > on the DPCD helpers. But if we now agree that this is the preferred way >> > > to do things, then we should at least agree that it applies to all areas >> > > for the sake of consistency. >> > > >> > > Also, it might be worth looking into improving the structures, and maybe >> > > adding new ones to order things more conveniently or at least group them >> > > in some logical way. In my opinion some of our data structures are >> > > becoming somewhat... unwieldy. >> > >> > We're pretty good at consuming fairly invasive refactorings in drm-misc. >> > So it just boils down to get some agreement on what things should look >> > like (+1 from my side to parsing stuff into structs as a general idea), >> > and then massaging all the existing users of the "wrong" interface using >> > cocci and sed. >> > >> > Unfortunately "just" ;-) >> >> I think by now it would be useful to have a nested structure within >> struct drm_display_info that contains HDMI specific bits. We already >> have a number of candidates that could be extracted into such a >> structure (drm_detect_hdmi_monitor(), drm_detect_monitor_audio(), >> drm_rgb_quant_range_selectable(), ...). >> >> Another possibility would be to subclass struct drm_display_info, as >> in: >> >> struct drm_hdmi_info { >> struct drm_display_info display; >> >> /* HDMI specific information */ >> ... >> }; >> >> Or yet another would be to create struct drm_hdmi_info as a separate >> structure and provide a helper which will extract the necessary info >> from the EDID. Drivers could then store that in driver-private data >> whereas struct drm_display_info could be reduced to the generic bits >> that it used to have. > > I think nested drm_hdmi_info within drm_display_info sounds like a fine > idea. > -Daniel -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
