On 04/01/2016 12:03 AM, Tomi Valkeinen wrote:
On 01/04/16 03:46, Hans Verkuil wrote:
Apparently we set it always to 0 in
hdmi4_core.c:hdmi_core_powerdown_disable(), but never enable it. I guess
it only affects core irqs, so there have been no side effects.
But it would make sense to either have a matching call in the enable
path, or then just set it to 0 when initializing the IP.
I think it should be set in hdmi_core_video_config(). It sets other
SYS_CTRL1 bits there as
well, and that is probably why I missed it. I just never realized that
the PD bit wasn't set
there.
Hmm. Well, it's "power-down". It's quite unclear what it actually does,
but from the name of it, I think it makes sense to set it only when HDMI
core is enabled.
In hdmi4.c, there are hdmi_power_on_core() and hdmi_power_off_core()
functions, those might be good places to handle the bit.
Ehh... Actually, looking at the code more carefully...
hdmi_core_powerdown_disable() is called from hdmi4_configure() when
setting everything up, and there's a comment "power down off". So
apparently the intention of the code is to disable power-down mode, but
it sets the bit to a wrong state.
So probably we could just fix hdmi_core_powerdown_disable(), so that it
sets PD to 1, which is what it was meant to do. This assumes that there
are no bad side effects having PD 1 even if the HDMI is blanked, which
is something we need to verify. I can do a few tests with that.
Sounds good. BTW, I got confused yesterday by the name 'powerdown_disable()'.
How about calling it 'powerup()'? :-)
Regards,
Hans
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