[lm-sensors] [PATCH] coretemp: fix reading of microcode revision

[Jean Delvare]

Hi Jan,

On Fri, 08 Oct 2010 08:05:21 +0100, Jan Beulich wrote:
> >>> On 07.10.10 at 20:46, Fenghua Yu <fenghua.yu at intel.com> wrote:
> > On Thu, Oct 07, 2010 at 02:36:01AM -0700, Jan Beulich wrote:
> >> @@ -327,8 +336,13 @@ static int __devinit coretemp_probe(stru
> >>  
> >>  	if ((c->x86_model == 0xe) && (c->x86_mask < 0xc)) {
> >>  		/* check for microcode update */
> >> -		rdmsr_on_cpu(data->id, MSR_IA32_UCODE_REV, &eax, &edx);
> >> -		if (edx < 0x39) {
> >> +		err = smp_call_function_single(data->id, get_ucode_rev_on_cpu,
> >> +					       &edx, 1);
> >> +		if (err)
> >> +			dev_warn(&pdev->dev,
> >> +				 "Cannot determine microcode revision "
> >> +				 "of the CPU!\n");
> > 
> > When err, need to call dev_err and go to exit_free. This error handling 
> > should
> > be same as edx < 0x39 case.
> 
> Hmm, not sure - I'd prefer to consider the machine usable in this
> (theoretical only anyway) case.

I tend to prefer Fenghua's approach, sorry. If a bad microcode revision
is so wrong that we fail the probe when we see it, then a failure to
determine the microcode revision should lead to the same result. As
always, missing monitoring information is preferable to unreliable
monitoring information.

-- 
Jean Delvare