* [PATCH v2] Documentation: kernel-parameters.txt Add drm_kms_helper.poll
[not found] <id:1349364527.4583.24.camel@mattotaupa>
@ 2012-10-09 9:18 ` mika.kuoppala
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From: mika.kuoppala @ 2012-10-09 9:18 UTC (permalink / raw)
To: paulepanter; +Cc: dri-devel, Mika Kuoppala
From: Mika Kuoppala <mika.kuoppala@intel.com>
Possibility to disable polling to find connected displays was
introduced by commit [1]:
commit e58f637bb96d5a0ae0919b9998b891d1ba7e47c9
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri Aug 20 09:13:36 2010 +0100
drm/kms: Add a module parameter to disable polling
Add description for this parameter to kernel-parameters.txt
[1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=e58f637bb96d5a0ae0919b9998b891d1ba7e47c9
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
---
Documentation/kernel-parameters.txt | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f777fa9..0f0f071 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -741,6 +741,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
if its name and a colon are prepended to the EDID
name.
+ drm_kms_helper.poll=
+ Polling for connected display devices on older systems
+ without Hot Plug Detect (HPD) support, can be quite
+ expensive. Poll will happen periodically and can in
+ worst cases take several hundred milliseconds,
+ depending on the hardware. This will cause visible
+ stalls, for example in video playback. These stalls
+ might happen even when your video is on HDP output
+ but you have other non HDP outputs in your hw
+ configuration. If you experience stalls in display
+ output occurring every 10 seconds, disabling polling
+ might help. With polling disabled you need to manually
+ use xrandr to trigger detection.
+ Format: <bool> (1/Y/y=enable, 0/N/n=disable)
+ default: enabled
+
dscc4.setup= [NET]
dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
--
1.7.9.5
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2012-10-09 9:18 ` [PATCH v2] Documentation: kernel-parameters.txt Add drm_kms_helper.poll mika.kuoppala
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