IMPORTANT NOTE: *** This is just an experimental patch! ***

I fell over some "pipe A assertion" warnings while playing with drm-intel-nightly and contacted Daniel Vetter via PM.

[ dmesg ] [ 19.948476] WARNING: at drivers/gpu/drm/i915/intel_display.c:1228 assert_pipe+0xde/0xe0 [i915]() [ 19.948476] Hardware name: 530U3BI/530U4BI/530U4BH [ 19.948477] pipe A assertion failure (expected on, current off)

Waiting for a reply, I looked into the code myself and found this snippet and reflected about adding a quirk_pipea_force for my Intel SandyBridge GPU:

static struct intel_quirk intel_quirks[] = { /* HP Mini needs pipe A force quirk (LP: #322104) */ { 0x27ae, 0x103c, 0x361a, quirk_pipea_force }, ... }

Unfortunately, it was not clear to me what each value of the triple means.

I started to investigate more in the logs:

[ Xorg.0.log ] [ 16.421] (--) PCI:*(0:0:2:0) 8086:0116:144d:c0c7 rev 9, Mem @0xf0000000/4194304, 0xe0000000/268435456, I/O @ 0x00003000/64

This line gave me a 1st impression how my triple for a quirk line could look like!

Finally, Jani Nikula gave me some helpful explanations in [1]:

I guess you figured it out, but just a few lines up there's [1]:

struct intel_quirk { int device; int subsystem_vendor; int subsystem_device; void (*hook)(struct drm_device *dev); };

where device, subsystem_vendor, and subsystem_device map to Device, SVendor, and SDevice of the gfx controller in 'lspci -vmnn' output.

With these informations, I checked immediately here with 'lspci -vmnn' [2]:

Device: 00:02.0 Class: VGA compatible controller [0300] Vendor: Intel Corporation [8086] Device: 2nd Generation Core Processor Family Integrated Graphics Controller [0116] SVendor: Samsung Electronics Co Ltd [144d] SDevice: Device [c0c7] Rev: 09

[ Triple revealed (w/o brackets) ] Device (here: [0116]), SVendor (here: [144d]) and SDevice (here: [c0c7])

As a conclusion, I added the below QUIRK and it was successful:

[ dmesg ] [ 15.047921] [drm] applying pipe a force quirk

Daniel removed the "buggy" patch which introduced the warning for non-HSW GPUs. v3 in commit 693101618a4b [3] should be the revised patch.

[ References ] [1] http://lists.freedesktop.org/archives/intel-gfx/2013-January/024160.html [2] http://lists.freedesktop.org/archives/intel-gfx/2013-January/024161.html [3] http://cgit.freedesktop.org/~danvet/drm-intel/commit/?h=drm-intel-nightly&am...

Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Jani Nikula jani.nikula@linux.intel.com Cc: intel-gfx intel-gfx@lists.freedesktop.org Cc: DRI dri-devel@lists.freedesktop.org Signed-off-by: Sedat Dilek sedat.dilek@gmail.com --- drivers/gpu/drm/i915/intel_display.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 8c432a4..705fdb6 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8607,6 +8607,9 @@ static const struct intel_dmi_quirk intel_dmi_quirks[] = { };

static struct intel_quirk intel_quirks[] = { + /* Samsung NP530U3B-A01DE needs pipe A force quirk */ + { 0x0116, 0x144d, 0xc0c7, quirk_pipea_force }, + /* HP Mini needs pipe A force quirk (LP: #322104) */ { 0x27ae, 0x103c, 0x361a, quirk_pipea_force },