[systemd-bugs] [Bug 56159] New: System starts with LLVM driver sometimes

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=56159

          Priority: medium
            Bug ID: 56159
          Assignee: systemd-bugs at lists.freedesktop.org
           Summary: System starts with LLVM driver sometimes
        QA Contact: systemd-bugs at lists.freedesktop.org
          Severity: normal
    Classification: Unclassified
                OS: All
          Reporter: cosimoc at gnome.org
          Hardware: Other
            Status: NEW
           Version: unspecified
         Component: general
           Product: systemd

I have a laptop with a very fast SSD - on this machine sometimes (I'd say 1 out
of 5 boot attempts) it happens that the system starts up using the LLVM driver
instead of the Intel driver.

I asked Ray if he had any idea how this could happen, and he has a possible
explaination:
- logind is the component being responsible to set the right ACLs on the drm
device, by reading the uaccess tag, and it seems to check for it at startup and
on VT change
- it might happen that logind is pulled in very early in the boot process,
possibly before the drm device has been tagged at all
- under these circumstances, the ACLs won't be set (as there's no tag yet) and
as there's no VT switch, the drm device won't have the right permissions once X
starts, causing the fallback to LLVM
- this also seems to be consistent with the fact that it doesn't happen at
every boot, as the timings between different runs might differ

I have only seen the bug on my laptop with an SSD. Other machines I have with
rotating drives have never been affected.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/systemd-bugs/attachments/20121018/6cd05b59/attachment.html>