linux-kernel - Re: [PATCH 3/3] ACPI video: Fix applying indexed initial brightness value.

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Message-ID: <5142E20C.40805@web.de>
Date:	Fri, 15 Mar 2013 09:55:40 +0100
From:	Danny Baumann <dannybaumann@....de>
To:	Aaron Lu <aaron.lu@...el.com>
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 3/3] ACPI video: Fix applying indexed initial brightness
 value.

Hi,

 >> +static unsigned long long
>> +acpi_video_index_to_level(struct acpi_video_device *device,
>> +			  unsigned long long index)
>> +{
>> +	if (device->brightness->flags._BCL_reversed)
>> +		index = device->brightness->count - 3 - index;
>> +
>> +	return device->brightness->levels[index + 2];
>> +}
>
> What about making this function also take care of the
> bqc_offset_aml_bug_workaround? so that this function serves more like a
> conversion from raw value to fixed value, the function name can perhaps
> be named as: acpi_video_fix_bqc_value, or whatever you think is more
> appropriate.

Makes sense to me. How about acpi_video_bqc_to_level? I'd suggest 
acpi_video_bqc_value_to_level, but that makes it hard to keep the 80 
char limit in acpi_video_device_lcd_get_level_current.

>> @@ -742,9 +749,7 @@ acpi_video_init_brightness(struct acpi_video_device *device)
>>   				}
>>   		}
>>   	} else {
>> -		if (br->flags._BCL_reversed)
>> -			level_old = (br->count - 1) - level_old;
>> -		level = br->levels[level_old];
>> +		level = acpi_video_index_to_level(device, level_old);
>
> And here, that new function should be used, which also takes care of the
> offset_aml_bug problem(though in theory, the two problems may not happen
> on the same BIOS table).

But that new function (whatever it's named) is already used here?

BTW, shouldn't the use_bios_initial_backlight also be respected for the 
BQC-returns-index case? Currently it's only used for the 
BQC-returns-level case.

> And the acpi_video_device_lcd_get_level_current's param init can
> probably be renamed as raw, meaning if raw value is desired or fixed
> value, but it's not a big deal.

Agreed. I'll send a new patch set (this time with signed-off-by) once I 
get opinion on the question above.

Thanks,

Danny
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