Re: RTC problem on 8208CA

[Paul Gortmaker <p_gortmaker@yahoo.com>]

At a glance this sounds like the case of having the HPET enabled causes
the RTC IRQ functionality to become crippled or non-functional.  The
concept of hwclock using alarm or similar to handle broken and
misconfigured hardware is a sensible idea.

Paul.

--- Horms <horms@verge.net.au> wrote:

> Hi,
> 
> I am doing some investigations into a problem that has been reported
> with RTC on some Dell Machines.  It seems to be relate exclusively to
> machines that have the 8208CA ICH3 I/O Hub. I have been able to
> reproduce this on a Dell 8400, which I have access to today while I am
> on holidays. The output of lspci -v -x is attached.
> 
> For reference this problem is being tracked at
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=277298
> 
> There are various user-space work arounds for this problem, but I would
> like to offer what I have discovered from a brief poke-around in rtc.c.
> 
> An strace of hwclock looks a bit like this
> 
> open("/dev/rtc", O_RDONLY|O_LARGEFILE);
> ioctl(3, RTC_UIE_ON, 0);
> read(3, ...
> 
> the read never returns.
> 
> If my reading of the code is correct, what is occuring is that
> rtc_read() is in its do/while loop, waiting to be rescheduled. This
> should occur once an interupt is handled by rtc_interrupt(), but I guess
> that this is not occuring. Any insights into why this might be happening
> would be more than welcome.
> 
> The kernel in question is Ubuntu's 2.6.8.1, the rtc.c is identical from
> what was in linus' tree this morning. The config is also attached.
> 
> Please CC me on replies
> 
> Thanks
> 
>

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