[Intel-gfx] Speed boost disabling RCC clock gating ECO
pcjc2 at cam.ac.uk
Fri Oct 29 19:34:37 PDT 2010
Just a note on a data-point I found here:
sudo intel_reg_read 0x21D0
[sudo] password for pcjc2:
0x21D0 : 0x307
sudo intel_reg_write 0x21D0 0x1000207
Value before: 0x307
Value after: 0x207
This boosted FPS of my displaylist frame benchmark from 35fps to 37fps.
This was clearing bit 8 of ECOSKPD, which is controlling the following
Clock gating for the RCC (Disable one clock gate cell)
Any chance someone knows why the ECO is in place, or whether it is
dangerous to disable?
I also noticed that the specs for bit 12 and 9 (working around a CLIP
bug) are set in an invalid state according to the G45 PRM.
I have bit 12=0, bit9=1
This does match the expected default setting though.. is there a typo in
the PRM (Vol1a, P.322.) mixing bits 9 and 12 around in the table?
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