I just committed the following cange to the OpenBSD inteldrm(4) driver, which currently is mostly a port of the Linux 3.14 codebase. This enables the GSE interrupt on Broadwell. Without this interrupt, the ASLE backlight brightness mechanism doesn't work. I've verified that this fixed the ACPI _BCM/_BCQ-based brightness mechanism on a MacBookPro12,1 and a 3rd gen Lenovo X1 Carbon. And as far as I can tell the current Linux code still doesn't enable the GSE interrupt. So people over there might want to consider a diff like the one below. Cheers. Mark Index: i915_irq.c =================================================================== RCS file: /cvs/src/sys/dev/pci/drm/i915/i915_irq.c,v retrieving revision 1.29 diff -u -p -r1.29 i915_irq.c --- i915_irq.c 23 Sep 2015 23:12:12 -0000 1.29 +++ i915_irq.c 1 Dec 2015 20:43:05 -0000 @@ -3019,6 +3019,10 @@ static void gen8_de_irq_postinstall(stru I915_WRITE(GEN8_DE_PORT_IMR, ~GEN8_AUX_CHANNEL_A); I915_WRITE(GEN8_DE_PORT_IER, GEN8_AUX_CHANNEL_A); POSTING_READ(GEN8_DE_PORT_IER); + + I915_WRITE(GEN8_DE_MISC_IMR, ~GEN8_DE_MISC_GSE); + I915_WRITE(GEN8_DE_MISC_IER, GEN8_DE_MISC_GSE); + POSTING_READ(GEN8_DE_MISC_IER); } static int gen8_irq_postinstall(struct drm_device *dev) _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
