This is a note to let you know that I've just added the patch titled drm/i915: set backlight duty cycle after backlight enable for gen4 to the 3.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-i915-set-backlight-duty-cycle-after-backlight-enable-for-gen4.patch and it can be found in the queue-3.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 2e7eeeb59a92d09144fdb7d2dc1af77a10a7945b Mon Sep 17 00:00:00 2001 From: Jani Nikula <jani.nikula@xxxxxxxxx> Date: Mon, 9 Jun 2014 18:24:34 +0300 Subject: drm/i915: set backlight duty cycle after backlight enable for gen4 From: Jani Nikula <jani.nikula@xxxxxxxxx> commit 2e7eeeb59a92d09144fdb7d2dc1af77a10a7945b upstream. For reasons I can't claim to fully understand gen4 seems to require backlight duty cycle setting after the backlight has been enabled, or else black screen follows. I don't have documentation for the correct sequence on gen4 either. Confirmed on Dell Latitude D630 and MacBook4,1. This fixes a regression introduced by commit b35684b8fa94e04f55fd38bf672b737741d2f9e2 Author: Jani Nikula <jani.nikula@xxxxxxxxx> Date: Thu Nov 14 12:13:41 2013 +0200 drm/i915: do full backlight setup at enable time Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=75791 Reported-and-tested-by: mcy@xxxxxx Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79423 Reported-and-tested-by: Marc Milgram <mmilgram@xxxxxxxxxx> Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_panel.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -723,9 +723,6 @@ static void i965_enable_backlight(struct ctl = freq << 16; I915_WRITE(BLC_PWM_CTL, ctl); - /* XXX: combine this into above write? */ - intel_panel_actually_set_backlight(connector, panel->backlight.level); - ctl2 = BLM_PIPE(pipe); if (panel->backlight.combination_mode) ctl2 |= BLM_COMBINATION_MODE; @@ -734,6 +731,8 @@ static void i965_enable_backlight(struct I915_WRITE(BLC_PWM_CTL2, ctl2); POSTING_READ(BLC_PWM_CTL2); I915_WRITE(BLC_PWM_CTL2, ctl2 | BLM_PWM_ENABLE); + + intel_panel_actually_set_backlight(connector, panel->backlight.level); } static void vlv_enable_backlight(struct intel_connector *connector) Patches currently in stable-queue which might be from jani.nikula@xxxxxxxxx are queue-3.15/drm-i915-set-backlight-duty-cycle-after-backlight-enable-for-gen4.patch queue-3.15/drm-i915-default-to-having-backlight-if-vbt-not-available.patch queue-3.15/drm-i915-hold-the-table-lock-whilst-walking-the-file-s-idr-and-counting-the-objects-in-debugfs.patch queue-3.15/drm-i915-disable-fbc-by-default-also-on-haswell-and-later.patch queue-3.15/drm-i915-reorder-semaphore-deadlock-check.patch queue-3.15/drm-i915-avoid-div-by-zero-when-pixel_multiplier-is-zero.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html