Aaron Sowry
2010-Oct-29 15:49 UTC
[Nouveau] nouveau exposes backlight controls in presence of ACPI
It seems to be de facto standard to only expose kernel-level backlight controls in the absence of ACPI, however nouveau does this regardless of whether ACPI equivalents are available or not. This will confuse userspace in some situations. Does this need patching or is there some reason for this behaviour? /Aaron -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 489 bytes Desc: Digital signature URL: <http://lists.freedesktop.org/archives/nouveau/attachments/20101029/30cdc604/attachment.pgp>
Ben Skeggs
2010-Nov-02 03:58 UTC
[Nouveau] nouveau exposes backlight controls in presence of ACPI
On Fri, 2010-10-29 at 17:49 +0200, Aaron Sowry wrote:> It seems to be de facto standard to only expose kernel-level backlight controls in the absence of ACPI, however nouveau does this regardless of whether ACPI equivalents are available or not. This will confuse userspace in some situations. Does this need patching or is there some reason for this behaviour?Yes, it appears that you're correct here. I took a look into what is supposed to happen, and it looks fairly trivial to implement and stop nouveau providing nv_backlight if video.ko is already providing it. However. There's also the platform-specific modules (thinkpad etc) that will provide their own backlight methods if the standard ACPI mechanism isn't available. I didn't see any immediately obvious way of knowing whether or not they were being provided. I'm not too certain the best way to deal with this, any ideas? :) Ben.> > /Aaron > _______________________________________________ > Nouveau mailing list > Nouveau at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/nouveau