Messages in this thread | | | Date | Wed, 8 Feb 2006 10:06:20 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH] [RESEND] Add Dell laptop backlight brightness display |
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Hi! On Út 07-02-06 13:55:02, Matthew Garrett wrote: > On Tue, Feb 07, 2006 at 01:37:06PM +0000, Richard Purdie wrote: > > On Tue, 2006-02-07 at 13:23 +0000, Matthew Garrett wrote: > > > Would you be open to adding generic support for displaying separate AC > > > and DC brightnesses? Making it driver specific leaves the potential for > > > inconsistencies. > > > > The problem is that AC or DC is not a generic property of backlights but > > specific to your problematic hardware case. You're going to have a to > > find a way to tell if its running on AC or not to report the right value > > in the manner the class requires. > > Cases rather than case, sadly. Determining whether the hardware is on AC > or not tends to be much more awkward than you'd think. On HPs, it seems > to be done by making a specific call to the embedded controller. This is > very model specific, whereas the brightness values aren't. It's also > likely to go horribly wrong if the hardware is trying to access the > embedded controller at the same time. Realistically, it's impossible > without making the driver depend on ACPI and exporting acpi_ac_get_state > from the ACPI layer, which would be a shame since the rest of the > functionality isn't ACPI dependent at all.
Depending on acpi does not seem that bad. And exporting acpi_ac_get_state is probably good idea for other reasons, too. (Look how powernow-k8 does it; it needs pretty reliable AC/DC info.) Pavel -- Web maintainer for suspend.sf.net (www.sf.net/projects/suspend) wanted... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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