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Hi Daniel,<br>
<br>
<div class="moz-cite-prefix">On 06/02/2016 10:19 PM, Daniel Vetter
wrote:<br>
</div>
<blockquote cite="mid:20160602141910.GL7231@phenom.ffwll.local"
type="cite">
<pre wrap="">On Wed, Jun 01, 2016 at 10:54:09AM +0800, Yakir Yang wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Daniel,
On 05/31/2016 10:38 PM, Daniel Vetter wrote:
</pre>
<blockquote type="cite">
<pre wrap="">On Tue, May 31, 2016 at 09:37:36PM +0800, Yakir Yang wrote:
</pre>
<blockquote type="cite">
<pre wrap="">The full name of PSR is Panel Self Refresh, panel device could refresh
itself with the hardware framebuffer in panel, this would make a lots
of sense to save the power consumption.
For example, when desktop haven't change the context for a long time,
then we could refresh the data to the hardware framebuffer of panel,
and then let panel enter into PSR mode. After that system could poweroff
the LCDC controller and eDP controller, just let panel refresh the screen
by itself.
It's hard to decide when panel should enter into PSR or exit from PSR, in
this time I chose to let the drm_vblank enable/disable event driver the PSR.
This thread is based on Mark's RK3399 VOP thread[0] and my RK3399 eDP
thread[1].
[0]: <a class="moz-txt-link-freetext" href="https://patchwork.kernel.org/patch/8886041/">https://patchwork.kernel.org/patch/8886041/</a>
[1]: <a class="moz-txt-link-freetext" href="https://patchwork.kernel.org/patch/9132713/">https://patchwork.kernel.org/patch/9132713/</a>
</pre>
</blockquote>
<pre wrap="">Looks like you didn't wire up the drm_framebuffer->funcs->dirty callback
for manual upload of simple clients like bootsplash or fbdev. I think
that's needed. At least it's needed for every other manual upload dsi and
edp psr implementation.
-Daniel
</pre>
</blockquote>
<pre wrap="">That's great, thanks for your remind. Seems like userspace which does
frontbuffer rendering must call this ioctl to flush out the changes on
manual-update display outputs. It's helpful to hook this callback to
notify eDP refresh the eDP RFB(remote frame buffer).
But I think this is hard to used on Rockchip eDP controller, Rockchip eDP
driver just used two modes, Sink Device PSR_S0 (PSR inactive), and Sink
Device PSR_S2 (PSR active, display from RFB).
I think the "dirty" callback is only used when Sink device enter into PSR_S3
mode (PSR active, capture and display), need to update the remote frame
buffer. But on Rockchip platform the panel would be very easy to lose frame
in this PSR mode. I'm confused in this case, so I didn't enable that.
If we didn't enable the PSR_S3 mode, then we don't need to update the panel
remote frame buffer, so this "->dirty" callback would be unused in this
case.
</pre>
</blockquote>
<pre wrap="">
Sorry missed your reply here somehow. Every time you don't scan out the
drm_framebuffer directly, but from any kind of intermediate buffer, you
_must_ implement the dirty callback. Usually the simplest way is to kick
the device out of self-refresh and arm the time to re-enter self-refresh.
</pre>
</blockquote>
<br>
Sounds good, use timer to driver the PSR status, and abandon the
vblank<br>
enable/disable event. Okay, I start to do some experiments.<br>
<br>
<blockquote cite="mid:20160602141910.GL7231@phenom.ffwll.local"
type="cite">
<pre wrap="">I'm not entirely clear where your RFB is, so no idea whether that is
scanning out from the drm_framebuffer data directly, or whether that's
some on-chip or in-sink framebuffer cache.
</pre>
</blockquote>
<br>
RFB is an in-sink framebuffer cache. When Sink enter into PSR_State1
or<br>
PSR_State3, then it can capture the eDP timing from source to update
the RFB.<br>
<br>
<img src="cid:part1.01040605.06000003@rock-chips.com" alt=""><br>
<br>
<blockquote cite="mid:20160602141910.GL7231@phenom.ffwll.local"
type="cite">
<pre wrap="">We have a ridiculously nasty testuite in i-g-t for all these cases (we use
it to validate our framebuffer compression code, psr code and soon also
dsi manual upload). Unfortunately it's not yet ported over to be a generic
testcase. But at least for PSR that would be easy, since every PSR panel
has eDP sink crc support. And the testcase does require some kind of
display CRC support to validate actual screen contents, as opposed to
what's in memory in the drm_framebuffer.
-Daniel
</pre>
</blockquote>
<br>
Sorry, I'm not very clear about what you mean, seems you have a
reference<br>
code about PSR test ;)<br>
<br>
Thanks,<br>
- Yakir<br>
<br>
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