[Intel-gfx] [PATCH] drm/i915: Fix __intel_wait_for_register_fw to not sleep in atomic

[Chris Wilson]

On Wed, May 10, 2017 at 05:19:32PM +0200, Daniel Vetter wrote:
> The unconditionally fallback to the blocking wait_for resulted in
> impressive fireworks at boot-up on my snb here. Make sure if we set
> the slow timeout to 0 that we never ever sleep. The tail of the
> callchain was
> 
> intel_wait_for_register
> -> __intel_wait_for_register_fw
>   -> usleep_range
>      -> BOOM
> 
> It blew up in intel_crt_detect load detection code on the
> ADPA_CRT_HOTPLUG_FORCE_TRIGGER in the ADPA register.
> 
> v2: Shut up gcc.

u32 uninitialized_var(reg_value) ?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre