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From: Axel Lin <axel.lin@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org,
	Michael Hennerich <michael.hennerich@analog.com>,
	Richard Purdie <rpurdie@rpsys.net>,
	device-drivers-devel@blackfin.uclinux.org
Subject: Re: [PATCH] backlight: Fix the logic to set bits in adp8860_bl and adp8870_bl drivers
Date: Sat, 14 Jan 2012 17:22:20 +0800	[thread overview]
Message-ID: <CAF+7xW=qATBpVy-wG6+Joq+LB19TmM6qJUxoOV0U7R8omLVrxw@mail.gmail.com> (raw)
In-Reply-To: <20120113141019.1fc1439e.akpm@linux-foundation.org>

>> diff --git a/drivers/video/backlight/adp8860_bl.c b/drivers/video/backlight/adp8860_bl.c
>> index 66bc74d..378276c 100644
>> --- a/drivers/video/backlight/adp8860_bl.c
>> +++ b/drivers/video/backlight/adp8860_bl.c
>> @@ -146,7 +146,7 @@ static int adp8860_set_bits(struct i2c_client *client, int reg, uint8_t bit_mask
>>
>>       ret = adp8860_read(client, reg, &reg_val);
>>
>> -     if (!ret && ((reg_val & bit_mask) == 0)) {
>> +     if (!ret && ((reg_val & bit_mask) != bit_mask)) {
>>               reg_val |= bit_mask;
>>               ret = adp8860_write(client, reg, reg_val);
>>       }
>> diff --git a/drivers/video/backlight/adp8870_bl.c b/drivers/video/backlight/adp8870_bl.c
>> index 6c68a68..6735059 100644
>> --- a/drivers/video/backlight/adp8870_bl.c
>> +++ b/drivers/video/backlight/adp8870_bl.c
>> @@ -160,7 +160,7 @@ static int adp8870_set_bits(struct i2c_client *client, int reg, uint8_t bit_mask
>>
>>       ret = adp8870_read(client, reg, &reg_val);
>>
>> -     if (!ret && ((reg_val & bit_mask) == 0)) {
>> +     if (!ret && ((reg_val & bit_mask) != bit_mask)) {
>>               reg_val |= bit_mask;
>>               ret = adp8870_write(client, reg, reg_val);
>>       }
>
> This patch is applicable to 3.2.x, but I don't know whether to route it
> to -stable becasue you didn't tell me what effect the patch has :(
>

It's because I don't have this hardware.
I just found the bug while reading the code.

I was thinking I should CC stable, but since the code is there for a long time
and I don't know any complains of the bug. So I didn't CC stable.

Michael, do you see any user-visible effects of the bug?

Thanks,
Axel

  reply	other threads:[~2012-01-14  9:22 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-13  8:15 [PATCH] backlight: Fix the logic to set bits in adp8860_bl and adp8870_bl drivers Axel Lin
2012-01-13 22:10 ` Andrew Morton
2012-01-14  9:22   ` Axel Lin [this message]
2012-01-16  8:33     ` Hennerich, Michael

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