svn commit: r288653 - in head/sys/dev/drm2: . i915

[Jean-Sébastien Pédron]

On 04.10.2015 11:46, Konstantin Belousov wrote:
> On Sun, Oct 04, 2015 at 07:45:37AM +0000, Adrian Chadd wrote:
>>   * Add missing case statement (gen == 3) in intel_gpu_reset().
> This seems to be wrong.  The i915 and G33 chipsets do not have registers
> declared in the 8xx chipset documentation.  More, i915 and G33 have different
> reset procedures.
> 
> The absence of '3' case was copied from the corresponding Linux kernel.
> Was this change tested, or is there a reference to upstream where the
> handling was added in this manner ?

You're right, even in Linux 3.8, the switch does not have a case for
generation 3.

>>   * Replace M_WAITOK with M_NOWAIT when the return value of malloc is checked (may be incorrect).
> This is also incorrect.  At least the modesetting pathes are executed in
> the syscall context, and sleeping is allowed; the modesetting locks were
> selected to make sleeping possible.  Using nowait causes random syscalls
> failure where the requests would succeed otherwise.

My reasoning was that M_WAITOK could make the display hang/unresponsive
while the memory is under pressure. The caller should be responsible for
handling the error instead.

In Linux, *alloc() calls may fail so application should already be
responsible for that.

-- 
Jean-Sébastien Pédron

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