[Intel-gfx] [PATCH 06/29] drm/i915: add support for SBI ops

Chris Wilson chris at chris-wilson.co.uk
Fri Apr 13 22:26:30 CEST 2012

On Fri, 13 Apr 2012 17:08:42 -0300, Eugeni Dodonov <eugeni.dodonov at intel.com> wrote:
> With Lynx Point, we need to use SBI to communicate with the display clock
> control. This commit adds helper functions to access the registers via
> SBI.
> v2: de-inline the function and address changes in bits names
> v3: protect operations with dpio_lock, increase timeout to 100 for
> paranoia sake.
> v1 Reviewed-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>

Hmm, busy-waits upon a register change. Does it have to be atomic? Can
it really be called in IRQ context? Can I have a sleepy version that
won't cause audible stutters for the normal case? (Admittedly
single-core processors are history...)

Chris Wilson, Intel Open Source Technology Centre

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