From: "Mario 'BitKoenig' Holbe" <Mario.Holbe@RZ.TU-Ilmenau.DE>
To: linux-kernel@vger.kernel.org
Subject: Re: 2.4.22: ide-scsi interfers with APM
Date: Tue, 16 Sep 2003 01:30:08 +0200 [thread overview]
Message-ID: <20030915233008.GA2457@darkside.22.kls.lan> (raw)
In-Reply-To: <20030914151352.GA1301@darkside.22.kls.lan>
On Sun, Sep 14, 2003 at 05:13:52PM +0200, Mario 'BitKoenig' Holbe wrote:
> ide-scsi works fine, if CONFIG_APM=m is defined:
> it does not, if CONFIG_APM is undefined:
>
> I have no explanation for this and no idea how to debug it
> down. Hopefully someone else is able to explain it to me.
Okay, now I'm able to explain it myself.
It's a timing issue.
After this it works well even with CONFIG_APM is undefined:
--- kernel-source-2.4.22.old/include/linux/ide.h 2003-09-15 09:49:34.000000000 +0200
+++ kernel-source-2.4.22/include/linux/ide.h 2003-09-15 21:22:57.000000000 +0200
@@ -271,7 +271,7 @@
#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)
#define WAIT_READY (5*HZ) /* 5sec - some laptops are very slow */
#else
-#define WAIT_READY (3*HZ/100) /* 30msec - should be instantaneous */
+#define WAIT_READY (4*HZ/100) /* 40msec - should be instantaneous */
#endif /* CONFIG_APM || CONFIG_APM_MODULE */
#define WAIT_PIDENTIFY (10*HZ) /* 10sec - should be less than 3ms (?), if all ATAPI CD is closed at boot */
#define WAIT_WORSTCASE (30*HZ) /* 30sec - worst case when spinning up */
There were no changes from 2.4.20 to 2.4.22 (with 2.4.20
everything worked fine), so I guess, other timings changed.
I *guess* the 30msecs was a bit strong for cd-drives in
2.4.20 too (btw. it doesnt matter, if I compile ide-scsi
as module and insmod/rmmod it a few times) but worked.
Somewhere in 2.4.21 things were changed somehow that
modified the timing hardly enough to cross the border.
> Do I have to expect any other interferences like this?
IMHO some ide-proof should have a look at it to answer
this.
regards,
Mario
--
Ho ho ho! I am Santa Claus of Borg. Nice assimilation all together!
prev parent reply other threads:[~2003-09-15 23:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-14 15:13 Mario 'BitKoenig' Holbe
2003-09-15 23:30 ` Mario 'BitKoenig' Holbe [this message]
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