error messages - was: xf86-video-intel 2.5.0 performance questions

[Tobias Hain]

Keith Packard wrote:

>> [drm:i915_getparam] *ERROR* Unknown parameter 5
>> set status page addr 0x01fff000
>
> As Julien said, this is just the user-mode driver checking for GEM
> support which isn't present in your old kernel. If it were the new 2D
> driver printing the message, we would have fixed it, but it's the old
> kernel driver. That old driver could be patched to not print the
> message.

When having problems with the intel driver, people's attention first get on
one of the many error messages almost any intel video configuration
exhibits. Among these messages are:

[6] exaCopyDirty: Pending damage region empty!
[6] (EE) intel(0): Unable to write to SDVOCTRL_E for SDVOB Slave 0x70.
[16](EE) intel(0): underrun on pipe A!
[5] mtrr: no MTRR for e0000000,10000000 found
[?] waiting for X server to shut down error setting MTRR (base = 0xe0000000,
size = 0x10000000, type = 1) Invalid argument (22)

The number in square brackets [?] corresponds to the number of hits in the
intel xorg video bugzilla.

Even without patching old kernel code, I can think of many ways to prevent
the latest *ERROR* Unknown parameter 5 message.

Somebody involved in driver development, knows to judge those message. E.g.
the underrun message is explained here:
https://bugs.freedesktop.org/show_bug.cgi?id=16833#c16

However the general user (or developer, but just not being a video driver
developer) is mislead by those bloating error messages. I think it would be
helpful for people trying to debug issues, if those error messages get
evaluated. Maybe some should be downgraded to warnings. Others may be
presented more descriptive.

With the recent addition of GEM and G4x code and the multitude of
configurations deployed (libdrm, kernel, mesa, xserver, ...) the number of
bugs/issues facing people increased and one of the first things they
encounter are often one of the above error messages.

Regards,
7oby