Hi,
On 06-02-18 01:32, Pandiyan, Dhinakaran wrote:
On Thu, 2018-02-01 at 13:31 +0100, Hans de Goede wrote:
Hi All,
As you may have heard I've recently been working on improving
Linux laptop battery life, specifically the OOTB experience
without tweaking any options such as e.g. powertop --auto-tune
would do, see:
https://fedoraproject.org/wiki/Changes/ImprovedLaptopBatteryLife
So far this is going quite nicely, it looks like Fedora 28
will have SATA ALPM (big win), autosuspend of USB Bluetooth HCIs
and snd_intel_hda powersaving all enabled OOTB.
Looking for more savings I've run some quick tests with
i915.enable_psr=1, this seems to be another nice win (for an idle
system) of aprox. 0.5W.
So as with the other 3 items I just mentioned I'm now looking into
somehow enabling this be default, at least one some models.
Currently I'm thinking doing a whitelist or blacklist (*) for this,
but first I think we need some more data about on how much models
this just works and where it is causing issues, as such I've done
a blog post to gather this data:
https://hansdegoede.livejournal.com/18653.html
So I will revisit this eventually, once people have had some time
to respond to this blog-post.
In the mean time I wonder if anyone can explain why this options
is currently disabled by default. E.g. are there any known specific
models laptops / panels which are causing issues, are the bugzillas
for this? Etc. ?
I somehow missed reading your post.
There are few issues I know of:
1) frame counter reset that causes long vblank waits
2) fbcon screen freeze
3) driver v/s HW aux channel usage needs to be serialized
4) occasional cursor lag
5) lack of IGT's to verify correctness
The first two have patches on the list, the third is being worked on.
Ok, what is the ETA of these fixes landing upstream and I assume
it is not a good idea to enable PSR (even on models where people
have reported it seems to work) until these are fixed?
The fourth needs investigation.
Also does anyone know if any problems are mainly panel or laptop
model specific ? I would expect this to mostly be panel specific
and not depend on the model laptop (given then certain models
ship with different panels over their production lifetime).
I am sure there are panel issues, but I haven't looked into them yet.
Like Rodrigo suggested, we probably have to rely on VBT for this and
enable PSR by default on only those panels.
So there is a VBT bit for this? Currently I only see the code check
the VBT for using full-off vs standby PSR mode and not for whether
to actually use PSR or not ?
If we can get this from the VBT that would be way better then building
a manual whitelist, which is the direction I'm currently considering.
Regards,
Hans
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