Subject: Re: Toshiba laptop wedging hard on disk activity.
To: Brett Lymn <>
From: Manuel Bouyer <>
List: current-users
Date: 02/07/2000 11:52:53
On Mon, Feb 07, 2000 at 02:06:14PM +1030, Brett Lymn wrote:
> I have updated the source on my machine at home, built a kernel and
> loaded it onto the laptop - it still hangs, the odd thing is that the
> HD seems to shutdown, the disk stops spinning but the HD led stays
> on.  I have done some digging around on the _old_ source (updating the
> laptop source is risky, given the disk habit ;-) and I have noticed
> there is a loop in wdc_exec_command in /usr/src/sys/kern/ic/wdc.c that
> waits on AT_DONE and tsleep's if the status is not AT_DONE straight
> away - I am suspicious of this loop, I tried putting a count into the
> loop to break it out after a number of times around, this changed the
> behaviour as I was able to do a "make depend" whereas before this
> would lock the machine up.  The machine still locked when I tried
> making a kernel with -j10 which makes be suspect there is some timing
> sensitive problem that happens to be hit with the combination of
> hardware I have at the moment :-(

This loop should be correct, the tsleep shouldn't be awaked if the AT_DONE
flag is not set. If this happens then there is a problem somewhere else.
Note that wdc_exec_command() is not called very often in normal operations
(only for a atactl I think).

Manuel Bouyer, LIP6, Universite Paris VI.