On 23/01/15 02:00, Haixia Shi wrote: > Hi Emil, > > On Thu, Jan 22, 2015 at 4:38 PM, Emil Velikov <emil.l.veli...@gmail.com> > wrote: >> On 22/01/15 22:23, Haixia Shi wrote: >>> Hi Emil >>> >>> On Thu, Jan 22, 2015 at 1:36 PM, Emil Velikov <emil.l.veli...@gmail.com> >>> wrote: >>>> Hi Haixia Shi, >>>> >>>> On 22/01/15 17:35, Haixia Shi wrote: >>>>> Try the render node first and use it if available. Otherwise fall back to >>>>> normal nodes. >>>>> >>>> What is the use-case for such a platform - I assume it's worth >>>> mentioning in the commit message ? >>>> >>>> No other platform picks the device at random as seen below. Why did you >>>> choose such an approach ? It seems like one can easily shoot themselves >>>> by using it. >>> >>> CC Stephane. The goal here is just to pick the first available node >>> for off-screen rendering only. >>> >> Hmm I'm guessing that using the drm/gbm platform is out of the question >> ? Iirc there has been a bit of love on the gbm topic, and afaiu this >> solution is to be used with minigbm ? > > Yes this solutions is to be used with minigbm. > >> >> What I'm thinking here is: >> If you're testing a device with provides two or more nodes (be that the >> classic card or the render ones), one cannot guarantee that the kernel >> module for hw#1 will be loaded first. Thus even if one presumes that >> they are working on (testing) hw#1 that may or may not be the case. >> >> Not 100% sure on the module order part, so I could be wrong. > > I don't have a good answer for that... any suggestion on how best to > pick the right one? > Might be worth having a look at how platform_drm does it. But we warned there be dragons :)
>>>>> + char *card_path; >>>>> + if (asprintf(&card_path, node_path_fmt, base + i) < 0) >>>>> + continue; >>>>> + >>>>> + dri2_dpy->fd = open(card_path, O_RDWR); >>>> If you open a normal node (card%d) I believe that you'll need an >>>> authenticate hook in dri2_egl_display_vtbl. Does things work without it >>>> on your system/platform ? >>> >>> You're correct; normal node would require the legacy auth hook, and it >>> would only work without auth if the process is run as root, which is >>> why we're trying render nodes first. >>> >> So you're saying that people without render nodes should run egl(mesa) >> as root ? That does not sound like a wise suggestion imho. >> >> Basically what I'm trying to say is - if you have a fall-back to normal >> nodes, some form of auth ought to be in place. > > I see your point. Would it be cleaner if we simply require render node > to be present? The normal node (card%d) and the auth hook is more > trouble than its worth. > It's up-to you if you want to keep it. I'm just pointing out that having a fall-back that (a) mostly fails, without giving a clear indication as to why, or (b) forces you to run the app as root is counter-intuitive (not the best security practise) for most people. -Emil _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
