[Qemu-devel] Re: [PATCH] pci: w1cmask[PCI_BRIDGE_CONTROL] initialized incorrectly

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jan 26, 2011 at 10:53:42PM +0900, Isaku Yamahata wrote:
> On Wed, Jan 26, 2011 at 03:46:01PM +0200, Michael S. Tsirkin wrote:
> > On Wed, Jan 26, 2011 at 10:17:48PM +0900, Isaku Yamahata wrote:
> > > The bit should be writable, not w1c.
> > > 
> > > 3.2.5.18 bridge control register
> > > bit 11 Discard Timer SERR# Enable
> > > 
> > >   When set to 1, this bit enables the bridge to assert SERR# on
> > >   the primary interface when either the Primary Discard Timer or
> > >   Secondary Discard Timer expires and a Delayed Transaction is
> > >   discarded from a queue in the bridge. The default state of this
> > >   bit must be 0 after reset.
> > >   0 - do not assert SERR# on the primary interface as
> > >   a result of the expiration of either the Primary
> > >   Discard Timer or Secondary Discard Timer
> > >   1 - assert SERR# on the primary interface if either
> > >   the Primary Discard Timer or Secondary Discard
> > >   Timer expires and a Delayed Transaction
> > 
> > Yes but
> > #define  PCI_BRIDGE_CTL_DISCARD_STATUS 0x400   /* Discard timer status */
> > 
> > So this is bit 10?
> 
> Oh, sorry. So wmask should be chenged.

Yes. does the below work?

commit 24ebb78e6ec19b39cd138d493a2859122110f9cb
Author: Michael S. Tsirkin <mst@redhat.com>
Date:   Wed Jan 26 15:55:07 2011 +0200

    pci: bridge control fixup
    
    PCI_BRIDGE_CTL_DISCARD_STATUS (bit 10 in bridge control register)
    is W1C so we should not make it writeable, otherwise the assert(!(wmask
    & w1cmask)) in pci_default_write_config() is hit
    
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
    Reported-by: Isaku Yamahata <yamahata@valinux.co.jp>

diff --git a/hw/pci.c b/hw/pci.c
index 044c4bd..712280a 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -641,7 +641,6 @@ static void pci_init_wmask_bridge(PCIDevice *d)
                  PCI_BRIDGE_CTL_FAST_BACK |
                  PCI_BRIDGE_CTL_DISCARD |
                  PCI_BRIDGE_CTL_SEC_DISCARD |
-                 PCI_BRIDGE_CTL_DISCARD_STATUS |
                  PCI_BRIDGE_CTL_DISCARD_SERR);
     /* Below does not do anything as we never set this bit, put here for
      * completeness. */