Hi Henrik, On Fri, Jul 27, 2012 at 08:12:46PM +0200, Henrik Rydberg wrote: > The behavior of the SMC has changed several times over the years, > causing read failures in the driver. It seems the problem can be > explained by a shift in SMC speed combined with improper action on > status codes. > > We should first wait for the SMC to settle, which was the most > frequent response on the old slow machines. Then, if the SMC is busy, > we need to try again later by resending the command. This was the most > likely response until 2012. Now, with a shorter wait time, we are > again most likely to poll while the SMC is settling, and as a result > we see high failure rates on many old and new models. > > With the distinction between busy and failure, we can also wait longer > before retrying, without sacrificing speed. This seems to bring > failures down to virtually zero on all models. > > Tested on: MBA1,1 MBA3,1 MBA5,1 MBA5,2 MBP9,2 > > Tested-by: Adam Somerville <[email protected]> > Tested-by: Hubert Eichner <[email protected]> > Signed-off-by: Henrik Rydberg <[email protected]>
Applied. > --- > Hi Guenter, > > It turns out the mid-2012 Macbooks need additional changes in order to > work reliably. Since the needed change is a great improvement also on > other problematic machines, it would make a lot of sense if this patch > could be squeezed into the merge window. > > As I mentioned in a previous mail, backporting e70acc100 by itself is > not a good idea, but together with this patch it should be ok. > I think the patches should mature a bit in mainline. We can decide in a month or so if we want to backport them to previous releases. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
