From: Paulo Zanoni Date: Fri, 19 Sep 2014 19:04:55 +0000 (-0300) Subject: drm/i915: add SW tracking to FBC enabling X-Git-Tag: omap-for-v3.19/fixes-rc1~80^2~79^2~33 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9adccc6063d1cf6ba38a5a26b87001554105be18;p=pandora-kernel.git drm/i915: add SW tracking to FBC enabling Currently, calling intel_fbc_enabled() will trigger a register read. And we call it a lot of times, even when FBC is disabled, so saving a few cycles would be a good thing. Another reason for this patch is because we currently call intel_fbc_enabled() while the HW is runtime suspended, so the read makes no sense and triggers a WARN. This happens even if FBC is disabled by default. Of course one could argue that we just shouldn't be calling intel_fbc_enabled() while the driver is runtime suspended, and I agree that's a good argument, but I still think that the reason explained in the first paragraph already justifies the patch. This problem can easily be reproduced with many subtests of igt/pm_rpm, and it is a regression introduced by: commit c5ad011d7d256ecbe173324029e992817194d2b0 Author: Rodrigo Vivi Date: Mon Aug 4 03:51:38 2014 -0700 drm/i915: FBC flush nuke for BDW Testcase: igt/pm_rpm/cursor (and others) Cc: Rodrigo Vivi Signed-off-by: Paulo Zanoni Reviewed-by: Rodrigo Vivi Signed-off-by: Daniel Vetter --- Reading git-diff-tree failed