Re: [PATCH] Documentation: kernel-parameters.txt Add drm_kms_helper.poll

On Thu, Oct 4, 2012 at 12:34 PM, mika.kuoppala@intel.com wrote:

From: Mika Kuoppala mika.kuoppala@intel.com

Add description for drm_kms_helper.poll module parameter introduced by commit: e58f637bb96d5a0ae0919b9998b891d1ba7e47c9

Signed-off-by: Mika Kuoppala mika.kuoppala@intel.com

Actually I've noticed even with just hdmi it stalls for long enough to miss a frame, on an otherwise idle system. Kernel testcases ftw, kms locking ftl :(

Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch

---

Documentation/kernel-parameters.txt | 11 +++++++++++ 1 file changed, 11 insertions(+)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index f777fa9..ad97749 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -741,6 +741,17 @@ 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 VGA devices on older systems
  

•                   can be quite expensive, causing latencies of
  

•                   several hundred milliseconds. This will cause visible
  

•                   stalls, for example in video playback. If you
  

•                   experience stalls in display output occurring every
  

•                   10 seconds (DRM_OUTPUT_POLL_PERIOD=(10*HZ)), disabling
  

•                   polling might help.
  

•                   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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