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Date: Wed, 20 Mar 2013 15:32:38 +0800
From: Aaron Lu <aaron.lu@...el.com>
To: Danny Baumann <dannybaumann@....de>
CC: linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
Zhang Rui <rui.zhang@...el.com>, Len Brown <lenb@...nel.org>
Subject: Re: [PATCH v4 1/3] ACPI video: Fix brightness control initialization
for some laptops.
On 03/20/2013 12:24 AM, Danny Baumann wrote:
> v3 incorporates Aaron's feedback, v4 fixes my inability to use git
> send-email properly. Sorry for that.
For the 3 patches, Reviewed-by: Aaron Lu <aaron.lu@...el.com>
BTW, you can put things like what has been changed in a new series in
patch 0.
Thanks,
Aaron
>
> Regards,
>
> Danny
>
> Am 19.03.2013 17:22, schrieb Danny Baumann:
>> In particular, this fixes brightness control initialization for all
>> devices that return index values from _BQC and don't happen to have the
>> initial index set by the BIOS in their _BCL table. One example for that
>> is the Dell Inspiron 15R SE (model number 7520).
>>
>> What happened for those devices is that acpi_init_brightness queried the
>> initial brightness by calling acpi_video_device_lcd_get_level_current.
>> This called _BQC, which returned e.g. 13. As _BQC_use_index isn't
>> determined at this point (and thus has its initial value of 0), the
>> index isn't converted into the actual level. As '13' isn't present in
>> the _BCL list, *level is later overwritten with brightness->curr, which
>> was initialized to max_level (100) before. Later in
>> acpi_init_brightness, level_old (with the value 100) is used as an index
>> into the _BCL table, which causes a value outside of the actual table to
>> be used as input into acpi_video_device_lcd_set_level(). Depending on
>> the (undefined) value of that location, this call will fail, causing the
>> brightness control for the device in question not to be enabled.
>>
>> Fix that by returning the raw value returned by the _BQC call in the
>> initialization case.
>>
>> Signed-off-by: Danny Baumann <dannybaumann@....de>
>> ---
>> drivers/acpi/video.c | 43 ++++++++++++++++++++++++++-----------------
>> 1 file changed, 26 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
>> index 313f959..09e4722 100644
>> --- a/drivers/acpi/video.c
>> +++ b/drivers/acpi/video.c
>> @@ -222,7 +222,7 @@ static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
>> int level);
>> static int acpi_video_device_lcd_get_level_current(
>> struct acpi_video_device *device,
>> - unsigned long long *level, int init);
>> + unsigned long long *level, bool raw);
>> static int acpi_video_get_next_level(struct acpi_video_device *device,
>> u32 level_current, u32 event);
>> static int acpi_video_switch_brightness(struct acpi_video_device *device,
>> @@ -236,7 +236,7 @@ static int acpi_video_get_brightness(struct backlight_device *bd)
>> struct acpi_video_device *vd =
>> (struct acpi_video_device *)bl_get_data(bd);
>>
>> - if (acpi_video_device_lcd_get_level_current(vd, &cur_level, 0))
>> + if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
>> return -EINVAL;
>> for (i = 2; i < vd->brightness->count; i++) {
>> if (vd->brightness->levels[i] == cur_level)
>> @@ -281,7 +281,7 @@ static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsig
>> unsigned long long level;
>> int offset;
>>
>> - if (acpi_video_device_lcd_get_level_current(video, &level, 0))
>> + if (acpi_video_device_lcd_get_level_current(video, &level, false))
>> return -EINVAL;
>> for (offset = 2; offset < video->brightness->count; offset++)
>> if (level == video->brightness->levels[offset]) {
>> @@ -452,7 +452,7 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
>>
>> static int
>> acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
>> - unsigned long long *level, int init)
>> + unsigned long long *level, bool raw)
>> {
>> acpi_status status = AE_OK;
>> int i;
>> @@ -463,6 +463,15 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
>> status = acpi_evaluate_integer(device->dev->handle, buf,
>> NULL, level);
>> if (ACPI_SUCCESS(status)) {
>> + if (raw) {
>> + /*
>> + * Caller has indicated he wants the raw
>> + * value returned by _BQC, so don't furtherly
>> + * mess with the value.
>> + */
>> + return 0;
>> + }
>> +
>> if (device->brightness->flags._BQC_use_index) {
>> if (device->brightness->flags._BCL_reversed)
>> *level = device->brightness->count
>> @@ -476,16 +485,14 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
>> device->brightness->curr = *level;
>> return 0;
>> }
>> - if (!init) {
>> - /*
>> - * BQC returned an invalid level.
>> - * Stop using it.
>> - */
>> - ACPI_WARNING((AE_INFO,
>> - "%s returned an invalid level",
>> - buf));
>> - device->cap._BQC = device->cap._BCQ = 0;
>> - }
>> + /*
>> + * BQC returned an invalid level.
>> + * Stop using it.
>> + */
>> + ACPI_WARNING((AE_INFO,
>> + "%s returned an invalid level",
>> + buf));
>> + device->cap._BQC = device->cap._BCQ = 0;
>> } else {
>> /* Fixme:
>> * should we return an error or ignore this failure?
>> @@ -703,7 +710,8 @@ acpi_video_init_brightness(struct acpi_video_device *device)
>> if (!device->cap._BQC)
>> goto set_level;
>>
>> - result = acpi_video_device_lcd_get_level_current(device, &level_old, 1);
>> + result = acpi_video_device_lcd_get_level_current(device,
>> + &level_old, true);
>> if (result)
>> goto out_free_levels;
>>
>> @@ -714,7 +722,7 @@ acpi_video_init_brightness(struct acpi_video_device *device)
>> if (result)
>> goto out_free_levels;
>>
>> - result = acpi_video_device_lcd_get_level_current(device, &level, 0);
>> + result = acpi_video_device_lcd_get_level_current(device, &level, true);
>> if (result)
>> goto out_free_levels;
>>
>> @@ -1268,7 +1276,8 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event)
>> goto out;
>>
>> result = acpi_video_device_lcd_get_level_current(device,
>> - &level_current, 0);
>> + &level_current,
>> + false);
>> if (result)
>> goto out;
>>
>>
>
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