Regards
Shashank
On 1/9/2018 11:31 PM, Ville Syrjälä wrote:
On Thu, Dec 28, 2017 at 08:32:05PM +0530, Sharma, Shashank wrote:
On 12/22/2017 11:58 PM, Ville Syrjala wrote:
From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
The LG 4k TV I have doesn't deassert HPD when I turn the TV off, but
when I turn it back on it will pulse the HPD line. By that time it has
forgotten everything we told it about scrambling and the clock ratio.
Hence if we want to get a picture out if it again we have to tell it
whether we're currently sending scrambled data or not. Implement
that via the encoder->post_hotplug() hook.
I am not sure if I understood the problem statement correctly. Even if
the TV triggers HPD line while turning it back, I would expect:
- EDID read for TV's detection, which will refresh SCDC and scrambling
capabilities
- A new modeset will be triggered, which will program the scrambling and
high tmds clock ratio again
- Once HDMI controller is programmed, it will generate scrambled signals
till next modeset / disable.
So why do we need to do this ? I might be missing something, but lets
discus about it.
The EDID is readable even when the HPD gets deasserted for a short
perios, hence we never consider the sink as being disconnected. Hence
there will be no modeset triggered by userspace.
This is a bigger problem then, in that case, the pipe/port would be
enabled, and IMHO I don't think fixing just the scrambling status is
right thing to do.
Also, is this the right behavior from the monitor ? I am also worried if
we are trying to fix the monitor's fault in our driver.
- Shashank
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