Re: [PATCH] drm/i915: storm detection documentation update

From: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: jani.nikula@intel.com, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: storm detection documentation update
Date: Wed, 08 Jul 2015 18:54:06 +0530	[thread overview]
Message-ID: <559D2476.9010003@intel.com> (raw)
In-Reply-To: <20150707113145.GM7568@phenom.ffwll.local>


On 7/7/2015 5:01 PM, Daniel Vetter wrote:
> On Tue, Jul 07, 2015 at 04:10:49PM +0530, Sivakumar Thulasimani wrote:
>> From: "Thulasimani,Sivakumar" <sivakumar.thulasimani@intel.com>
>>
>> Update the hotplug documentation to explain that hotplug storm
>> is not expected for Display port panels and hence is not handled
>> in current code.
>>
>> Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
>> ---
>>   drivers/gpu/drm/i915/intel_hotplug.c |    4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c
>> index bac91a1..7dc5e6a 100644
>> --- a/drivers/gpu/drm/i915/intel_hotplug.c
>> +++ b/drivers/gpu/drm/i915/intel_hotplug.c
>> @@ -66,6 +66,10 @@
>>    * while before being re-enabled. The intention is to mitigate issues raising
>>    * from broken hardware triggering massive amounts of interrupts and grinding
>>    * the system to a halt.
>> + *
>> + * Hotplug interrupt storm is not expected on Display port panel, hence the
>> + * current code only handles disabling and later enabling of HPD interrupts
>> + * for HDMI panels through the storm handling set of functions.
> This isn't accurate, we handle storms on everything _but_ DP (tv, vga,
> sdvo, ...). I'd go with
>
>   * Hotplug interrupt storm is not expected on Display port panel, hence the
>   * current code doesn't handle irq reenabling when a DP sink is connected
>   * and the hpd is handled by the DP callbacks. But on DP+ ports
>   * storms are still handled correctly in all other cases (e.g. due to HDMI
>   * sinks).
>
> Could still be improved I think.
>
> -Daniel
>
Sorry i don't get the "DP+" reference here. By DP+, do you mean dongles ?
passive dongles will report them selves as HDMI to respective detect 
routines
active dongles will be still treated as DP hence not handling HPD will 
apply to any
display connected through active dongle as well.

-- 
regards,
Sivakumar


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