diff options
Diffstat (limited to 'sys/dev/drm2/i915/intel_pm.c')
| -rw-r--r-- | sys/dev/drm2/i915/intel_pm.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/sys/dev/drm2/i915/intel_pm.c b/sys/dev/drm2/i915/intel_pm.c index ab9eee4..ddab457 100644 --- a/sys/dev/drm2/i915/intel_pm.c +++ b/sys/dev/drm2/i915/intel_pm.c @@ -3672,9 +3672,39 @@ static void gen6_init_clock_gating(struct drm_device *dev) ILK_DPARBUNIT_CLOCK_GATE_ENABLE | ILK_DPFDUNIT_CLOCK_GATE_ENABLE); + +#ifdef FREEBSD_WIP + /* NOTE Linux<->FreeBSD: Disable GEN6_MBCTL write. + * + * This arrived in Linux 3.6 in commit + * b4ae3f22d238617ca11610b29fde16cf8c0bc6e0 and causes significantly + * increased power consumption after kldloading i915kms.ko on FreeBSD + * on (some) Sandy Bridge laptops. A Thinkpad X220 reported about 11W + * after booting while idle at the vt(4) console and about double that + * after loading the driver. + * + * There were reports in Linux of increased consumption after a suspend + * and resume cycle due to that change. + * + * Linux bug reports: + * https://bugs.freedesktop.org/show_bug.cgi?id=54089 + * https://bugzilla.kernel.org/show_bug.cgi?id=58971 + * + * This suspend and resume issue is reportedly fixed in Linux with + * commits 7dcd2677ea912573d9ed4bcd629b0023b2d11505 and + * 7dcd2677ea912573d9ed4bcd629b0023b2d11505 (Linux 3.11). However, I + * found that those changes did not help on FreeBSD, where increased + * power consumption is observed after loading i915kms.ko without + * suspending and resuming. + * + * This workaround should be removed after updating to a future Linux + * i915 version and verifying normal power consumption on Sandy Bridge. + */ + /* WaMbcDriverBootEnable */ I915_WRITE(GEN6_MBCTL, I915_READ(GEN6_MBCTL) | GEN6_MBCTL_ENABLE_BOOT_FETCH); +#endif /* FREEBSD_WIP */ for_each_pipe(pipe) { I915_WRITE(DSPCNTR(pipe), |
