From: jsanka@codeaurora.org
To: Daniel Vetter <daniel@ffwll.ch>
Cc: 'Sean Paul' <seanpaul@chromium.org>, dri-devel@lists.freedesktop.org
Subject: Re: Support for early wakeup in DRM
Date: Thu, 20 Feb 2020 13:24:00 -0800 [thread overview]
Message-ID: <f4f899ae9b035e2eb5ddc89e3c1a120b@codeaurora.org> (raw)
In-Reply-To: <20200220201458.GB2363188@phenom.ffwll.local>
On 2020-02-20 12:14, Daniel Vetter wrote:
> On Thu, Feb 20, 2020 at 10:45:57AM -0800, jsanka@codeaurora.org wrote:
>> Hello All,
>>
>> I am seeking recommendations for DRM compatible methods of updating
>> the
> HW
>> other than frame commit path. When exiting idle/runtime_suspend, the
> driver
>> votes for a bunch of resources including power/clk/bandwidth as a part
> of
>> first commit handling. This usually adds a few millisecond delay
>> before
>> processing the frame. The requirement is to find possible ways to
>> reduce
>> this delay by providing an early intimation to the framework to
> "prepare"
>> the HW by voting for the resources and keep the HW ready to process an
>> imminent frame commit. Especially in performance oriented Automotive
> world,
>> these delays are very time critical and we are working on ways to
> mitigate
>> them.
>>
>>
>>
>> DRM framework converges all the parameters affecting the HW in terms
>> of
> DRM
>> properties in a single COMMIT call. To address the above issue, we
>> need
> a
>> parallel channel which should allow the framework to make necessary
> changes
>> to the HW without violating the master access privileges.
>>
>>
>>
>> Before resorting to custom downstream ways, I want to check with the
>> community for folks who might have encountered and resolved such
>> issues.
>
> Just enable the display, which will grab all the clocks and everything?
> Once the display is on a commit should be possible on the next frame,
> at
> least for well-working drivers.
> -Daniel
>
I believe even to turn on the display, DRM will need an explicit commit
(probably without any planes/pixel buffers). For cases like smart
panels, where we can keep the panel on(panel internal RAM refresh) and
power collapse the display HW, resuming back with an explicit commit
will push a black (or default color programmed in the HW) frame causing
a glitch.
Thanks and Regards,
Jeykumar S.
>>
>>
>>
>> Thanks and Regards,
>>
>> Jeykumar S
>>
>> Qualcomm Inc.
>>
>>
>>
>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-02-20 21:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 18:45 Support for early wakeup in DRM jsanka
2020-02-20 20:14 ` Daniel Vetter
2020-02-20 21:24 ` jsanka [this message]
2020-02-21 17:20 ` Daniel Vetter
2020-02-22 20:10 ` jsanka
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f4f899ae9b035e2eb5ddc89e3c1a120b@codeaurora.org \
--to=jsanka@codeaurora.org \
--cc=daniel@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=seanpaul@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox