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From: Blue Swirl <blauwirbel@gmail.com>
Date: Sun, 26 Jul 2009 16:40:50 +0300
Message-ID: <f43fc5580907260640w7000415am1120b3d9354484a4@mail.gmail.com>
Subject: Re: [Qemu-devel] [patch] esp.c fast SCSI-bus reset
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To: Artyom Tarasenko <atar4qemu@googlemail.com>
Cc: qemu-devel <qemu-devel@nongnu.org>

On Fri, Jul 24, 2009 at 1:21 PM, Artyom
Tarasenko<atar4qemu@googlemail.com> wrote:
> It seems to make a little sense to raise an interrupt still having
> "bus reset" status, since it makes the host think the bus is busy.
> The proper way would be to tell all the scsi devices to reset before
> the interrupt.
> The patch makes scsi probe to come a little further when using OBP
> under sparc32.

Unfortunately it also makes BSDs think that the bus reset hasn't happened:
OpenBSD 4.3 (RAMDISK) #415: Tue Mar 11 18:31:57 MDT 2008
    deraadt@sparc.openbsd.org:/usr/src/sys/arch/sparc/compile/RAMDISK

[clip]

esp0 at dma0 offset 0x8800000 pri 4: ESP200, 40MHz, SCSI ID 7
scsibus0 at esp0: 8 targets
esp0: waiting for SCSI Bus Reset to happen
probe(esp0:0:0): esp0: timed out [ecb 0xf9c2d000 (flags 0x3, dleft 24,
stat 0)], <state 9, nexus 0x0, phase(l 0, c 0, p 101), resid 0, msg(q
0,o 0) >
probe(esp0:0:0): esp0: timed out [ecb 0xf9c2d000 (flags 0x43, dleft
24, stat 0)], <state 9, nexus 0x0, phase(l 0, c 0, p 101), resid 0,
msg(q 0,o 0) > AGAIN
esp0: waiting for SCSI Bus Reset to happen

NetBSD just hangs:
NetBSD 4.0 (INSTALL) #0: Sun Dec 16 02:32:37 PST 2007
        builds@wb29:/home/builds/ab/netbsd-4-0-RELEASE/sparc/200712160005Z-obj/home/builds/ab/netbsd-4-0-RELEASE/src/sys/arch/sparc/compile/INSTALL

[clip]
esp0 at dma0 slot 5 offset 0x8800000 level 4: ESP200, 40MHz, SCSI ID 7
scsibus0 at esp0: 8 targets, 8 luns per target
ledma0 at sbus0 slot 5 offset 0x8400010: DMA rev 2
le0 at ledma0 slot 5 offset 0x8c00000 level 6: address 52:54:00:12:34:56
le0: 8 receive buffers, 2 transmit buffers
SUNW,CS4231 at sbus0 slot 4 offset 0xc000000 level 5 (ipl 9) not configured
power-management at sbus0 slot 4 offset 0xa000000 not configured
esp0: waiting for SCSI Bus Reset to happen
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0
md0: internal 688 KB image area
scsibus0: waiting 2 seconds for devices to settle...

Linux is not affected.