RE: [PATCH] intel_menlo: max_state is unsigned, invalid test

From: Thomas, Sujith
Date: Wed Nov 05 2008 - 05:21:56 EST




>-----Original Message-----
>From: Len Brown [mailto:lenb@xxxxxxxxxx]
>Sent: Tuesday, November 04, 2008 9:37 AM
>To: Andrew Morton; Thomas, Sujith; Zhang, Rui
>Cc: roel kluin; Brown, Len; Linux Kernel Mailing List; linux-
>acpi@xxxxxxxxxxxxxxx
>Subject: Re: [PATCH] intel_menlo: max_state is unsigned, invalid test
>
>
>
>On Mon, 3 Nov 2008, Andrew Morton wrote:
>
>> On Wed, 29 Oct 2008 17:06:47 -0400
>> roel kluin <roel.kluin@xxxxxxxxx> wrote:
>>
>> > max_state is unsigned, so the test is invalid.
>> >
>> > Signed-off-by: Roel Kluin <roel.kluin@xxxxxxxxx>
>> > ---
>> > I think max_state can only become -1, no? then probably a different
>> > patch is required.
>> > I may not be able to respond for a few weeks.
>> >
>> > diff --git a/drivers/misc/intel_menlow.c
b/drivers/misc/intel_menlow.c
>> > index e00a275..980171d 100644
>> > --- a/drivers/misc/intel_menlow.c
>> > +++ b/drivers/misc/intel_menlow.c
>> > @@ -121,7 +121,7 @@ static int memory_set_cur_bandwidth(struct
>thermal_cooling_device *cdev,
>> > if (memory_get_int_max_bandwidth(cdev, &max_state))
>> > return -EFAULT;
>> >
>> > - if (max_state < 0 || state > max_state)
>> > + if (max_state == -1 || state > max_state)
>> > return -EINVAL;
>> >
>> > arg_list.count = 1;
>> >
>>
>> hm, maybe.
>>
>> This can only happen if acpi_evaluate_integer(MEMORY_GET_BANDWIDTH)
>> returned no-error and a bandwidth of zero (I assume).
>>
>> Is this a special case which the driver really wanted to handle? If
>> so, why is "0" the only bad value which we're checking for? Or is
this
>> all some big brainfart which should be removed?
>
>Sujith,
>Please send me a patch to intel_menlo.c that documents the
>legal return values from GTHS.
>
>If 0 is illegal, that is fine, but the upstream driver doesn't
>check for it properl (I like Rui's 9/11 patch better than the above,
>so andrew, you can drop this patch in any case)
>
>thanks,
>-Len
>
>ps. Sujith, shouldn't there be a MAINTAINERS for this driver with your
>name on it?
>
>
Hi Len,
I am also in agreement that Rui's 9/11 patch is the solution.
I'll be sending out patches you requested.
These can be applied over Rui's 9/11 patch.

Regards,
Sujith

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