Re: 2,6.26-rc4-git2 - long pause during boot

[Andrew Morton <akpm@linux-foundation.org>]

On Fri, 6 Jun 2008 06:07:29 +0000 Chris Clayton <chris2553@googlemail.com> wrote:

> On Friday 06 June 2008, Andrew Morton wrote:
> > On Sun, 1 Jun 2008 04:15:05 +0000 Chris Clayton <chris2553@googlemail.com> 
> wrote:
> > > Hi,
> > >
> > > I've just started testing 2.6.26 on my desktop machine and have found
> > > that I get a long pause (20 seconds or so) as the system boots. By pause
> > > I mean that the boot messages that normally scroll by stop doing so for,
> > > as I say, about 20 seconds.
> > >
> > > I've done a bisect and arrived at:
> > >
> > > b0ed43360fdca227048d88a08290365cb681c1a8 is first bad commit
> > > commit b0ed43360fdca227048d88a08290365cb681c1a8
> > > Author: Hannes Reinecke <hare@suse.de>
> > > Date:   Tue Mar 18 14:32:28 2008 +0100
> > >
> > >     [SCSI] add scsi_host and scsi_target to scsi_bus
> > >
> > >     This patch implements scsi_host and scsi_target device types
> > >     and adds both to the scsi_bus.
> > >
> > >     Signed-off-by: Hannes Reinecke <hare@suse.de>
> > >     Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
> > >     Signed-off-by: James Bottomley
> > > <James.Bottomley@HansenPartnership.com>
> > >
> > > :040000 040000 4e3140909966b4c9aa987d34ee4078d283fe0351
> > >
> > > 46e4fd28cc537ba700eb4f5652abf043fed4d76d M      drivers
> > >
> > > The config file for that kernel is attached as are the kernel log for
> > > booting that kernel and the bisect log.
> > >
> > > I've also noticed that it takes much longer for icons to appear on my
> > > desktop when I plug a usb storage device in. (The icons are shown/hidden
> > > by a simple sctript that is run via udev when the device is
> > > attached/detached.)
> >
> > Do you believe that this is the same period?  20 seconds?
> >
> 
> Thanks for the reply, Andrew. I was beginning to think that I'd committed an 
> LKML sin :-)

Well you did - you reported a bug.

<watches wodim wibble for five minutes then report "CD/DVD-Recorder
not ready."  Pretends not to have noticed.>

> Yes, it is about the same. On 2.6.25.4 (and earlier), the icons appear within a 
> second or two, but with 2.6.26-rc2 or later, it takes about 20 seconds. I've 
> now built and installed -rc5 and am seeing the same behaviour.
> 
> I've also built -rc5 on my laptop. On that my kernel uses the older IDE drivers 
> rather than libata. The boot proceeds with no pause, but I do see the same 
> delay in the desktop icons appearing when I attach a usb-storage device.

OK that makes sense.  ata and usb use the scsi layer.  IDE does not.