* [RFC PATCH 4/5] ACPI video: support reversed _BCL method
@ 2009-03-10 8:03 Zhang Rui
2009-03-10 17:08 ` Matthew Garrett
2009-03-10 17:11 ` Matthew Garrett
0 siblings, 2 replies; 5+ messages in thread
From: Zhang Rui @ 2009-03-10 8:03 UTC (permalink / raw)
To: linux-acpi; +Cc: Len Brown, Thomas Renninger, Matthew Garrett, Zhang, Rui
Subject: support reversed _BCL method in ACPI video driver
From: Zhang Rui <rui.zhang@intel.com>
The brightness levels returned by _BCL package are in a reversed order
on some laptops.
http://bugzilla.kernel.org/show_bug.cgi?id=12037
http://bugzilla.kernel.org/show_bug.cgi?id=12302
http://bugzilla.kernel.org/show_bug.cgi?id=12235
sort the _BCL packge in case it's reversed.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
drivers/acpi/video.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
Index: linux-2.6/drivers/acpi/video.c
===================================================================
--- linux-2.6.orig/drivers/acpi/video.c
+++ linux-2.6/drivers/acpi/video.c
@@ -170,6 +170,7 @@ struct acpi_video_device_cap {
struct acpi_video_brightness_flags {
u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
+ u8 _BCL_reversed:1; /* _BCL package is in a reversed order*/
};
struct acpi_video_device_brightness {
@@ -746,9 +747,16 @@ acpi_video_init_brightness(struct acpi_v
count += level_ac_battery;
}
- /* don't sort the first two brightness levels */
- sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
- acpi_video_cmp_level, NULL);
+ /* Check if the _BCL package is in a reversed order */
+ if (max_level == br->levels[2]) {
+ br->flags._BCL_reversed = 1;
+ sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
+ acpi_video_cmp_level, NULL);
+ } else if (max_level != br->levels[count - 1]) {
+ ACPI_ERROR((AE_INFO,
+ "Brightness levels in _BCL is in a mess\n"));
+ goto out_free_levels;
+ }
br->count = count;
device->brightness = br;
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH 4/5] ACPI video: support reversed _BCL method
2009-03-10 8:03 [RFC PATCH 4/5] ACPI video: support reversed _BCL method Zhang Rui
@ 2009-03-10 17:08 ` Matthew Garrett
2009-03-10 17:11 ` Matthew Garrett
1 sibling, 0 replies; 5+ messages in thread
From: Matthew Garrett @ 2009-03-10 17:08 UTC (permalink / raw)
To: Zhang Rui; +Cc: linux-acpi, Len Brown, Thomas Renninger
On Tue, Mar 10, 2009 at 04:03:31PM +0800, Zhang Rui wrote:
> + } else if (max_level != br->levels[count - 1]) {
> + ACPI_ERROR((AE_INFO,
> + "Brightness levels in _BCL is in a mess\n"));
> + goto out_free_levels;
Again, I don't think failing here is the best thing - I think bizarre
behaviour is preferable to entirely unworking.
--
Matthew Garrett | mjg59@srcf.ucam.org
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH 4/5] ACPI video: support reversed _BCL method
2009-03-10 8:03 [RFC PATCH 4/5] ACPI video: support reversed _BCL method Zhang Rui
2009-03-10 17:08 ` Matthew Garrett
@ 2009-03-10 17:11 ` Matthew Garrett
2009-03-11 1:42 ` Zhang Rui
1 sibling, 1 reply; 5+ messages in thread
From: Matthew Garrett @ 2009-03-10 17:11 UTC (permalink / raw)
To: Zhang Rui; +Cc: linux-acpi, Len Brown, Thomas Renninger
On Tue, Mar 10, 2009 at 04:03:31PM +0800, Zhang Rui wrote:
> sort the _BCL packge in case it's reversed.
What code actually uses this? A later patch seems to check it in the
indexed case, but I can't find a reference to using it in the
non-indexed case.
--
Matthew Garrett | mjg59@srcf.ucam.org
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH 4/5] ACPI video: support reversed _BCL method
2009-03-10 17:11 ` Matthew Garrett
@ 2009-03-11 1:42 ` Zhang Rui
2009-03-11 1:45 ` Matthew Garrett
0 siblings, 1 reply; 5+ messages in thread
From: Zhang Rui @ 2009-03-11 1:42 UTC (permalink / raw)
To: Matthew Garrett; +Cc: linux-acpi, Len Brown, Thomas Renninger
On Wed, 2009-03-11 at 01:11 +0800, Matthew Garrett wrote:
> On Tue, Mar 10, 2009 at 04:03:31PM +0800, Zhang Rui wrote:
> > sort the _BCL packge in case it's reversed.
>
> What code actually uses this? A later patch seems to check it in the
> indexed case, but I can't find a reference to using it in the
> non-indexed case.
>
It's just used in the indexed case.
In bug http://bugzilla.kernel.org/show_bug.cgi?id=12249
Name (PCTG, Package (0x10)
{
0x64,
0x5A,
0x55,
0x50,
0x4B,
0x46,
0x41,
0x3C,
0x37,
0x32,
0x2D,
0x28,
0x23,
0x1E,
0x19,
0x14
})
Method (_BCL, 0, NotSerialized)
{
Return (PCTG)
}
Method (_BQC, 0, NotSerialized)
{
Return (LBTN)
}
device->brightness->levels[] = {0x64, 0x5A, 0x14, 0x19,..., 0x5a, 0x64};
The index value returned by _BQC is the index in the PCTG package.
if the _BCL package is in a reversed order, we can not use this index to
get the value in device->brightness->levels[].
For example, if the current brightness is 0x64, _BQC returns 0 in this
case, but we can not translate this to value 0x14, we need a flag to
tell us that _BCL is reversed.
But in the non-indexed case, _BQC always returns a percentage that can
be used directly by ACPI video driver, i.e. we don't need to parse
device->brightness->levels to get the real value. so we don't need to
check the device->brightness->flags._BCL_reversed bit.
thanks,
rui
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC PATCH 4/5] ACPI video: support reversed _BCL method
2009-03-11 1:42 ` Zhang Rui
@ 2009-03-11 1:45 ` Matthew Garrett
0 siblings, 0 replies; 5+ messages in thread
From: Matthew Garrett @ 2009-03-11 1:45 UTC (permalink / raw)
To: Zhang Rui; +Cc: linux-acpi, Len Brown, Thomas Renninger
On Wed, Mar 11, 2009 at 09:42:55AM +0800, Zhang Rui wrote:
> The index value returned by _BQC is the index in the PCTG package.
> if the _BCL package is in a reversed order, we can not use this index to
> get the value in device->brightness->levels[].
> For example, if the current brightness is 0x64, _BQC returns 0 in this
> case, but we can not translate this to value 0x14, we need a flag to
> tell us that _BCL is reversed.
>
> But in the non-indexed case, _BQC always returns a percentage that can
> be used directly by ACPI video driver, i.e. we don't need to parse
> device->brightness->levels to get the real value. so we don't need to
> check the device->brightness->flags._BCL_reversed bit.
Ah, of course. Sorry, I should have got that. Thanks for the
explanation!
Acked-by: Matthew Garrett <mjg@redhat.com>
--
Matthew Garrett | mjg59@srcf.ucam.org
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^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2009-03-11 1:45 UTC | newest]
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2009-03-10 8:03 [RFC PATCH 4/5] ACPI video: support reversed _BCL method Zhang Rui
2009-03-10 17:08 ` Matthew Garrett
2009-03-10 17:11 ` Matthew Garrett
2009-03-11 1:42 ` Zhang Rui
2009-03-11 1:45 ` Matthew Garrett
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