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由 Ville Syrjälä 提交于
BSpec says: "Overlay Clock Gating Must be Disabled: Overlay & L2 Cache clock gating must be disabled in order to prevent device hangs when turning off overlay.SW must turn off Ovrunit clock gating (6200h) and L2 Cache clock gating (C8h)." We only turned off the overlay clock gating (due to lack of docs I presume). After a bit of experimentation it looks like the the magic C8h register lives in the PCI config space of device 0, and the magic bit appears to be bit 2. Or at the very least this eliminates the GPU death after MI_OVERLAY_OFF. L2 clock gating seems to save ~80mW, so let's keep it on unless we need to actually use the overlay. Also let's move the OVRUNIT clock gating to the same place since we can, and 845 supposedly doesn't need it. Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1481131693-27993-11-git-send-email-ville.syrjala@linux.intel.comAcked-by: NChris Wilson <chris@chris-wilson.co.uk>
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