linux-next: suspend tree build warnings

linux-next: suspend tree build warnings

[Stephen Rothwell]

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Hi Rafael,

Today's linux-next build (x86_64 allmodconfig) produced these warnings:

drivers/media/dvb/frontends/dib7000p.c: In function ‘dib7000p_i2c_enumeration’:
drivers/media/dvb/frontends/dib7000p.c:1315: warning: the frame size of 2256 bytes is larger than 2048 bytes
drivers/media/dvb/frontends/dib3000mc.c: In function ‘dib3000mc_i2c_enumeration’:
drivers/media/dvb/frontends/dib3000mc.c:853: warning: the frame size of 2160 bytes is larger than 2048 bytes

Introduced by commit 99307958cc9c1b0b2e0dad4bbefdafaf9ac5a681 ("PM:
Introduce core framework for run-time PM of I/O devices (rev. 17)").

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

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Re: linux-next: suspend tree build warnings

[Rafael J. Wysocki]

On Wednesday 19 August 2009, Stephen Rothwell wrote:
> Hi Rafael,

Hi,

> Today's linux-next build (x86_64 allmodconfig) produced these warnings:
> 
> drivers/media/dvb/frontends/dib7000p.c: In function ‘dib7000p_i2c_enumeration’:
> drivers/media/dvb/frontends/dib7000p.c:1315: warning: the frame size of 2256 bytes is larger than 2048 bytes
> drivers/media/dvb/frontends/dib3000mc.c: In function ‘dib3000mc_i2c_enumeration’:
> drivers/media/dvb/frontends/dib3000mc.c:853: warning: the frame size of 2160 bytes is larger than 2048 bytes
> 
> Introduced by commit 99307958cc9c1b0b2e0dad4bbefdafaf9ac5a681 ("PM:
> Introduce core framework for run-time PM of I/O devices (rev. 17)").

Well.

This commit increases the size of struct device quite a bit and both of the
drivers above create a "state" object on the stack that contains struct device
among other things.

I think they should allocate these objects using kmalloc() and I don't know
what I can do about this, really.  Maybe except for modifying the drivers to
use kmalloc().

Thanks,
Rafael

Re: linux-next: suspend tree build warnings

[Greg KH]

On Wed, Aug 19, 2009 at 11:38:03PM +0200, Rafael J. Wysocki wrote:
> On Wednesday 19 August 2009, Stephen Rothwell wrote:
> > Hi Rafael,
> 
> Hi,
> 
> > Today's linux-next build (x86_64 allmodconfig) produced these warnings:
> > 
> > drivers/media/dvb/frontends/dib7000p.c: In function ‘dib7000p_i2c_enumeration’:
> > drivers/media/dvb/frontends/dib7000p.c:1315: warning: the frame size of 2256 bytes is larger than 2048 bytes
> > drivers/media/dvb/frontends/dib3000mc.c: In function ‘dib3000mc_i2c_enumeration’:
> > drivers/media/dvb/frontends/dib3000mc.c:853: warning: the frame size of 2160 bytes is larger than 2048 bytes
> > 
> > Introduced by commit 99307958cc9c1b0b2e0dad4bbefdafaf9ac5a681 ("PM:
> > Introduce core framework for run-time PM of I/O devices (rev. 17)").
> 
> Well.
> 
> This commit increases the size of struct device quite a bit and both of the
> drivers above create a "state" object on the stack that contains struct device
> among other things.

Ick.  struct device should _never_ be on the stack, why would this code
want to do such a thing?

thanks,

greg k-h

Re: linux-next: suspend tree build warnings

[Andy Walls]

On Wed, 2009-08-19 at 16:36 -0700, Greg KH wrote:
> On Wed, Aug 19, 2009 at 11:38:03PM +0200, Rafael J. Wysocki wrote:
> > On Wednesday 19 August 2009, Stephen Rothwell wrote:
> > > Hi Rafael,
> > 
> > Hi,
> > 
> > > Today's linux-next build (x86_64 allmodconfig) produced these warnings:
> > > 
> > > drivers/media/dvb/frontends/dib7000p.c: In function ‘dib7000p_i2c_enumeration’:
> > > drivers/media/dvb/frontends/dib7000p.c:1315: warning: the frame size of 2256 bytes is larger than 2048 bytes
> > > drivers/media/dvb/frontends/dib3000mc.c: In function ‘dib3000mc_i2c_enumeration’:
> > > drivers/media/dvb/frontends/dib3000mc.c:853: warning: the frame size of 2160 bytes is larger than 2048 bytes
> > > 
> > > Introduced by commit 99307958cc9c1b0b2e0dad4bbefdafaf9ac5a681 ("PM:
> > > Introduce core framework for run-time PM of I/O devices (rev. 17)").
> > 
> > Well.
> > 
> > This commit increases the size of struct device quite a bit and both of the
> > drivers above create a "state" object on the stack that contains struct device
> > among other things.
> 
> Ick.  struct device should _never_ be on the stack, why would this code
> want to do such a thing?

It appears that the state object is a dummy being used to detect and
twiddle some identical chips on the i2c bus.  The functions called only
use the "i2c_adapter" and "cfg" member of the dummy state object, but
those functions want that state object as an input argument.

<obvious>
The simplest fix is dynamic allocation of the dummy state object with
kmalloc() and then to free it before exiting the function.
</obvious>

Regards,
Andy


> thanks,
> 
> greg k-h

Re: linux-next: suspend tree build warnings

[Patrick Boettcher]

Hi,

On Wed, 19 Aug 2009, Andy Walls wrote:
>> Ick.  struct device should _never_ be on the stack, why would this code
>> want to do such a thing?

When you are doing a thing it does not necessarily you know that you're 
doing it.

> It appears that the state object is a dummy being used to detect and
> twiddle some identical chips on the i2c bus.  The functions called only
> use the "i2c_adapter" and "cfg" member of the dummy state object, but
> those functions want that state object as an input argument.
>
> <obvious>
> The simplest fix is dynamic allocation of the dummy state object with
> kmalloc() and then to free it before exiting the function.
> </obvious>

Even more obvious: Fix the function with simpler code to do the same 
thing.

I will try to fetch some time from somewhere to work on it.

--

Patrick 
http://www.kernellabs.com/