46ddf19477
Provide a standardized sysfs interface for setting min, and max frequencies. The code which reads the limits were lifted from the debugfs files. As a brief explanation, the limits are similar to the CPU p-states. We have 3 states: RP0 - ie. max frequency RP1 - ie. "preferred min" frequency RPn - seriously lowest frequency Initially Daniel asked me to clamp the writes to supported values, but in conforming to the way the cpufreq drivers seem to work, instead return -EINVAL (noticed by Jesse in discussion). The values can be used by userspace wishing to control the limits of the GPU (see the CC list for people who care). v4: Make exceeding the soft limits return -EINVAL as well (Daniel) v3: bug fix (Ben) - was passing the MHz value to gen6_set_rps instead of the step value. To fix, deal only with step values by doing the divide at the top. v2: add the dropped mutex_unlock in error cases (Chris) EINVAL on both too min, or too max (Daniel) v2 Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> CC: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> |
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