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Date:      Wed, 8 Jan 1997 08:07:39 -0500
From:      "Steve Sims" <SimsS@IBM.Net>
To:        "Hackers" <Hackers@FreeBSD.ORG>
Cc:        <toor@dyson.iquest.net>
Subject:   Bounce Buffers and CCD
Message-ID:  <199701081309.NAA198420@smtp-gw01.ny.us.ibm.net>

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I've had a bounty of problems getting `ccd` to work with my Adaptech 1542-CF.
 

Under 2.2-mumble the symptoms were the dreaded:
	vm_bounce_alloc: b_bufsize(0x80) < b_count(0x200) !!
	panic: vm_bounce_alloc
error.  Worked fine with only 16 Meg installed, I assumed that this "might"
have been fixed in -CURRENT, sup'd that, rebuilt everything.  Still no go.

So I turned to the archives to see if this was FAQ and stumbled across the
attached message (patch included).

I figured that I had nothing to lose, so I 'patch < /tmp/foo', rebuilt
kernel, reboot - SUCCESS!  (Thanks, John!)

Question:  Is there any reason that this one-liner has not been folded in to 
-CURRENT, -STABLE, and kin?  

Related point:  I believe it was Terry Lambert that stated in previous
messages (words to the effect) that "option BOUNCE_BUFFERS" is not *strictly*
needed; that this functionality is automatically enabled on ISA systems with
>16Meg and that including "options BOUNCE_BUFFERS" in late-model kernel
configs only serves to *force* BOUNCE_BUFFERS on ISA systems with =< 16Meg. 
I don't concur.  Removing "options BOUNCE_BUFFERS" on a 32Meg system will
page-fault-panic a booting box as quickly as anything else I've ever tried! 
(Terry, I hope I haven't quoted you out of context, but I'm here to tell ya':
BOUNCE-BUFFERS is a MANDATORY option for >16M systems, at least on
3.0-CURRENT with my mo-bo having PCI, ISA and VESA!)

...sjs...
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<Picture>


Date:      Fri, 6 Sep 1996 22:50:07 -0500 (EST)
From:      "John S. Dyson" <toor@dyson.iquest.net>
To:        gordon@drogon.net (Gordon Henderson)
Cc:        questions@freebsd.org, scsi@freebsd.org
Sender:    owner-questions@freebsd.org
Subject:   Re: CCD Setup woes ... (Kernel Panic)






>=20
> I'm tring to get a CCD going as an experiment and it's causing the =
kernel
> to panic.=20
>=20
Yep, there is a problem with CCD using the FreeBSD bounce scheme.  Of =
course,
it is only noticed on ISA systems.

>=20
> which resulted in a kernel panic. The message is:
>=20
>   vm_bounce_alloc: b_bufsize(0x80) < b_count(0x200) !!
>   panic: vm_bounce_alloc
>=20
b_bufsize is not being setup correctly in ccd (I think).

>
> followed by the usual syncing disks bit. The number in the b_bufsize() =

> varies from crash to crash.
>=20
> Am I doing anything obviously wrong?
>=20
No.

Hope the following works for you!!!  If it does, let me know so that
I can commit it.

Try this patch to ccd relative to -current (the equiv patch might
work for -stable), I haven't tested this though:


Index: ccd.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /local/home/ncvs/src/sys/dev/ccd/ccd.c,v
retrieving revision 1.16
diff -C5 -r1.16 ccd.c
*** ccd.c	1996/07/24 23:45:24	1.16
--- ccd.c	1996/09/07 03:46:27
***************
*** 909,918 ****
--- 909,920 ----
  	else
  		cbp->cb_buf.b_bcount =3D dbtob(cs->sc_ileave - cboff);
  	if (cbp->cb_buf.b_bcount > bcount)
  		cbp->cb_buf.b_bcount =3D bcount;
 =20
+ 	cbp->cb_buf.b_bufsize =3D cbp->cb_buf.b_bcount;
+=20
  	/*
  	 * context for ccdiodone
  	 */
  	cbp->cb_obp =3D bp;
  	cbp->cb_unit =3D cs - ccd_softc;








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