[Bug 198669] Driver crash at radeon_ring_backup+0xd3/0x140 [radeon]

[bugzilla-daemon@bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=198669

--- Comment #10 from Christian König (christian.koenig@amd.com) ---
(In reply to roger@beardandsandals.co.uk from comment #9)
> The most likely cause of this kind of mechanical issue is the signal path
> between the video interface hardware and the outside world, either a dry
> joint or a mechanical fault in the cable or cable connectors.

That is what I absolutely agree about.

> The driver has sufficient
> information to determine that a hard failure has occured, and that failure
> is probably not in the gpu itself. I would like to see the driver doing a
> hard reset of the card with rigorous error checking. If it cannot reset the
> GPU in graphical mode it should try to set the display hardware into a basic
> console mode.

And that is the part you don't seem to understand. The driver is trying exactly
what you are describing.

We detect a problem because of a timeout, e.g. the hardware doesn't respond in
a given time frame on commands we send to it.

What we do then is to query the hardware how far we proceeded in the execution
and the hardware answered with a nonsense value. In other words bits are set in
the response which should never be set.

This is a clear indicator that the PCIe transaction for the register read
aborted because the device doesn't response any more.

The most likely cause of that is that the bus interface in the ASIC locked up
because of an electrical problem (I think the ESD protection kicked in) and the
only way to get out of that is a hard reset of the system.

What we can try to do is trying to prevent further failures like the crash you
described by checking the values read from the hardware. This way you can at
least access the box over the network or blindly shut it down with keyboard
short cuts.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel