Re: [PATCH v2] drm/radeon: Retry DDC probing on DVI on failure if we got an HPD interrupt
From: Christian KÃnig
Date: Fri Dec 04 2015 - 04:55:01 EST
On 04.12.2015 10:43, Boszormenyi Zoltan wrote:
2015-12-04 09:53 keltezÃssel, Christian KÃnig Ãrta:
On 04.12.2015 00:26, cpaul@xxxxxxxxxx wrote:
From: Lyude <cpaul@xxxxxxxxxx>
HPD signals on DVI ports can be fired off before the pins required for
DDC probing actually make contact, due to the pins for HPD making
contact first. This results in a HPD signal being asserted but DDC
probing failing, resulting in hotplugging occasionally failing.
This is somewhat rare on most cards (depending on what angle you plug
the DVI connector in), but on some cards it happens constantly. The
Radeon R5 on the machine used for testing this patch for instance, runs
into this issue just about every time I try to hotplug a DVI monitor and
as a result hotplugging almost never works.
Rescheduling the hotplug work for a second when we run into an HPD
signal with a failing DDC probe usually gives enough time for the rest
of the connector's pins to make contact, and fixes this issue.
Signed-off-by: Lyude <cpaul@xxxxxxxxxx>
I find a second a bit long, but if it works so what?
Looks sane enough to me, patch is Reviewed-by: Christian KÃnig <christian.koenig@xxxxxxx>
Does this patch help in case of the Radeon chip only has HDMI and DP outputs
exposed (Zotac ZBOXNANO-AQ01) but used with DVI or VGA monitors with
converter cables? We have some problems with such scenarios that sounds
eerily similar to this description.
No, at least active converter cables are a completely different case.
Regards,
Christian.
Inquiry-by: ZoltÃn BÃszÃrmÃnyi <zboszor@xxxxx>
;-)
Thanks in advance.
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