From: "Michael S. Tsirkin" <mst@redhat.com>
To: qemu-devel@nongnu.org, zltjiangshi@gmail.com,
Aurelien Jarno <aurelien@aurel32.net>
Subject: [Qemu-devel] bonito: PCI_STATUS questions
Date: Wed, 27 Oct 2010 18:12:28 +0200 [thread overview]
Message-ID: <20101027161227.GA9873@redhat.com> (raw)
I see code in bonito.c that clears bits:
PCI_STATUS_REC_MASTER_ABORT | PCI_STATUS_REC_TARGET_ABORT
on each read and write.
However
1. I don't see anything in code that would set these bits
2. The PCI spec says this about the status register:
Reads to this register behave normally. Writes are slightly different in
that bits can be reset, but not set. A one bit is reset (if it is not
read-only) whenever the register is written, and the write data in the
corresponding bit location is a 1. For instance, to clear bit 14 and not
affect any other bits, write the value 0100_0000_0000_0000b to the
register.
while the code in bonito.c resets the bits to 0 on each write.
Comments?
--
MST
next reply other threads:[~2010-10-27 14:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-27 16:12 Michael S. Tsirkin [this message]
2010-10-28 0:57 ` [Qemu-devel] Re: bonito: PCI_STATUS questions chen huacai
2010-10-28 4:54 ` Michael S. Tsirkin
2010-10-28 8:31 ` chen huacai
2010-10-29 8:16 ` Michael S. Tsirkin
2010-10-29 13:34 ` chen huacai
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