On Tue, Jan 22, 2019 at 3:26 AM Christopher James Halse Rogers <r...@ubuntu.com> wrote: > > On 18 December 2018 7:07:01 pm NZDT, Christopher James Halse Rogers > <ch...@cooperteam.net> wrote: >> >> On 18 December 2018 4:35:37 am AEDT, Emil Velikov <emil.l.veli...@gmail.com> >> wrote: >>> >>> Hi Christopher, >>> >>> On Tue, 20 Nov 2018 at 03:37, Christopher James Halse Rogers >>> <christopher.halse.rog...@canonical.com> wrote: >>>> >>>> We can't use drmSetMaster to query whether or not a drm fd is master >>>> because it requires CAP_SYS_ADMIN, even if the fd *is* a master fd. >>>> >>> Can you please mention the exact use case here? You mentioned it over >>> IRC although it'll be nice to have it here for posterity. >> >> >> Certainly! >> >> The particular use-case I was hitting was testing my display server in a >> container, where container-root is not real-root but the implicit-master FD >> you get by opening the DRM node when there is no current master would be >> sufficient. >> >> Just assuming the FD we get is master and failing later breaks the platform >> probing; for example, when run under X11 if we don't check master we'll load >> the KMS platform and then fail, rather than noticing that KMS won't work and >> using our X11 backend. >> >> > >>>> >>>> Pick DRM_IOCTL_MODE_ATTACHMODE as a long-deprecated ioctl that is >>>> DRM_MASTER but not DRM_ROOT_ONLY as the probe by which we can detect >>>> whether or not the fd is master. >>>> >>> I'm wondering if we cannot extent DRM_IOCTL_GET_CLIENT or another >>> IOCTL. >>> What do you think? May I interest you in writing an RFC for the >>> kernel-side? >> >> >> I think if I was going to do kernel-side changes if probably just make it so >> that IOCTL_SET_MASTER just unconditionally succeeded on an fd that was >> already master?
Use-case seems all reasonable, I was waiting for a respin with my suggestion ... -Daniel >> ________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > Ping! > > Is there anything more you'd like to know about my use-case here? Are there > any objections to adding drmIsMaster()? > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
