News: 0001484509

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Linux's DRM Power Saving Policy Gets Reverted For Now

([Hardware] 3 Hours Ago Reverting Power Saving Policy)


Submitted for DRM-Next last week with intentions of getting it into the Linux 6.12 kernel was [1]a new DRM "power saving policy" property . The intent was for this new monitor/display connector property to indicate whether power saving features should be used that could compromise the experience intended by the desktop compositor. But one week later this property is now set to be removed as it's been deemed immature.

The Power Saving Policy for the connector currently can indicate whether the driver should require color accuracy and in turn for the driver/hardware to disable power saving features that could affect color fidelity. Another policy option is for requiring low-latency to disable power saving features that affect the display latency like Panel Self Refresh (PSR). While the ultimate intention of this feature is worthwhile, the support for the DRM core property and the AMDGPU driver integration is being reverted just one week after it was submitted to DRM-Next.

Developers have determined the property in its current form doesn't meet user-space requirements and that merging the property to the mainline kernel should wait until there is a user-space solution properly ready for merging.

AMD engineer Harry Wentland [2]commented last week on the mailing list after issues were raised over this Power Saving Policy property:

"I agree we should revert the KMS property until we have a userspace implementation that is reviewed and ready to be merged. It was merged based on a misunderstanding and shouldn't have been merged.

I don't think we should revert the sysfs property. The power savings to end-users can be significant. I would like to see compositors take control if it via the KMS property.

...

We have a good handful of widely used compositors. We have one PPD with a replacement for it in the works. A sysfs allows all users to get the power benefits even if compositors don't explicitly enable support for power saving features in KMS. The goal of PPD and co. is power savings while that is not always a primary goal for all compositors (even though compositors play a large role in a system's power usage)."

Thus with today's [3]drm-misc-next pull that Power Saving Policy property is being removed.



[1] https://www.phoronix.com/news/Linux-6.12-Power-Saving-Policy

[2] https://lists.freedesktop.org/archives/amd-gfx/2024-August/112106.html

[3] https://lore.kernel.org/dri-devel/20240809071241.GA222501@localhost.localdomain/T/#u


ahrs

emansom

Youth is not a time of life, it is a state of mind; it is a temper of
the will, a quality of the imagination, a vigor of the emotions, a predominance
of courage over timidity, of the appetite for adventure over love of ease.
Nobody grows old by merely living a number of years; people grow
old only by deserting their ideals. Years wrinkle the skin, but to give up
enthusiasm wrinkles the soul. Worry, doubt, self-distrust, fear, and despair
-- these are the long, long years that bow the head and turn the growing spirit
back to dust.
Whether seventy or sixteen, there is in every being's heart the love
of wonder, the sweet amazement at the stars and the starlike things and
thoughts, the undaunted challenge of events, the unfailing childlike appetite
for what next, and the joy and the game of life.
You are as young as your faith, as old as your doubt; as young as your
self-confidence, as old as your fear, as young as your hope, as old as your
despair.
So long as your heart receives messages of beauty, cheer, courage,
grandeur and power from the earth, from man, and from the Infinite, so long
you are young.
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