Hi,

On Thu, Sep 15, 2011 at 12:02 PM, Tomi Valkeinen [off-list ref] wrote:

On Thu, 2011-09-15 at 11:54 +0530, K, Mythri P wrote:

quoted

Hi,

On Thu, Sep 15, 2011 at 11:27 AM, Tomi Valkeinen [off-list ref] wrote:

quoted

On Thu, 2011-09-15 at 11:11 +0530, K, Mythri P wrote:

quoted

Hi,

On Wed, Sep 14, 2011 at 7:41 PM, Tomi Valkeinen [off-list ref] wrote:

quoted

quoted

Yes, you are right, detect() does not "know" if the monitor has changed
between polls, so both notification and polling are needed. I
implemented only polling as there's no HPD event mechanism yet in
omapdss, and also because this was simple and gives DRM basic ability to
detect a monitor.

If it is needed for DRM then it is fine, but with detect renamed to
poll. By next week i should have a patch ready for HPD event
mechanism.

What is wrong with "detect"? It detects if there's a display connected.
It can be used in polling manner, trying it every n seconds, but it
should also be used even if you use HPD event. I think the normal
sequence would be something like:

1) register HPD event
2) use detect() to see if a monitor is already connected

I guess polling ever few seconds to detect would be waste of CPU
cycles when there is already a mechanism in the H/w to detect the
connection.

Obviously. Polling is only used if hot-plug-detect is not available. But
detect function can be used even when HPD is available.

quoted

Current sequence :
Enable display ( Irrespective of whether the cable is connected on not)

Sequence with HPD:
1.Register for HPD connect.
2.Enable display
3.Notify DRM/Audio/Kernel component that wants to listen to this event.

Why would you enable the display even if there's no monitor connected?

And when the DRM starts, how does DRM know if the display was already
connected? Would you send a HPD event when DRM registers to the event
even if there's no actual plug-in event done (i.e. user actually
connecting the cable)?

HPD event would be triggered only when the cable is connected , and
the EDID is ready to be read by the monitor. So the question enabling
display doesnt exist. When HDMI is enabled in the HPD mode it will be
in minimal power mode.
Yes then the driver will notify DRM/any module that cable(monitor)  is
now connected.

And just to clarify, my sequence example was from DRM's point of view.
The HDMI driver shouldn't do anything before DRM/omapfb asks it to do
something.

 Tomi

Thanks and regards,
Mythri.