Re: [PATCH] pci: don't enable too much HT MSI mapping -v5 -resend

[Prakash Punnoor <prakash@punnoor.de>]

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On Samstag 28 März 2009 21:18:19 Yinghai Lu wrote:
> Prakash Punnoor wrote:
> > On Samstag 28 März 2009 13:34:44 Prakash Punnoor wrote:
> >> On Freitag 27 März 2009 00:10:01 Jesse Barnes wrote:
> >>> On Fri, 20 Mar 2009 19:29:41 -0700
> >>>
> >>> Yinghai Lu <yinghai@kernel.org> wrote:
> >>>> Impact: fix bug
> >>>>
> >>>> Prakash reported that his c51-mcp51 system ondie sound card doesn't
> >>>> work MSI but if he hack out the HT-MSI on mcp51, the MSI will work
> >>>> well with sound card.
> >>>>
> >>>> this patch rework the nv_msi_ht_cap_quirk()
> >>>> and will only try to avoid to enable ht_msi on device following that
> >>>> root dev, and don't touch that root dev
> >>>>
> >>>> v3: will enable c51...
> >>>> v4: will enable c51 kind of without leaf too.
> >>>> v5: update to mainline
> >>>>
> >>>> Reported-by: Prakash Punnoor <prakash@punnoor.de>
> >>>> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> >>>
> >>> Applied, thanks.  Prakash if you get a chance can you try testing my
> >>> linux-next branch (or just linux-next in general tomorrow) to make sure
> >>> this is still ok for you?
> >>>
> >>> Thanks,
> >>
> >> Finally I am able to test the linux-next branch of pci tree after Jesse
> >> gave some help with git.(Is it correct that the kernel calls itself
> >> 2.6.28-rc8? I looked into quirks.c and it seems to be correctly
> >> patched.) Unfortunately it doesn't seem to work for me (and I am
> >> wondering why as the old v4 version seemed to work ontop of one of the
> >> 2.6.29-rc versions):
> >>
> >> dmesg|grep HT
> >> pci 0000:00:00.0: Found disabled HT MSI Mapping
> >> pci 0000:00:03.0: Enabling HT MSI Mapping
> >> pci 0000:00:09.0: Found disabled HT MSI Mapping
> >> pci 0000:00:0e.0: Enabling HT MSI Mapping
> >> pci 0000:00:09.0: Found disabled HT MSI Mapping
> >> pci 0000:00:0f.0: Enabling HT MSI Mapping
> >> pci 0000:00:09.0: Found disabled HT MSI Mapping
> >> pci 0000:00:10.0: Enabling HT MSI Mapping
> >> pci 0000:00:09.0: Found disabled HT MSI Mapping
> >> pci 0000:00:10.1: Enabling HT MSI Mapping
> >>
> >> Device 09.0 doesn't get enabled (good) but 00.0 also not (bad). Then my
> >> Intel HDA cannot use MSI.
> >
> > I sprinkeld a few debugging messages around in the code and looking at
> > that I don't see how the code can enable NMSI for device 00.0, but not
> > for 09.0:
> >
> > Both will exit here:
> >
> > if (host_bridge == dev && host_bridge_with_leaf(host_bridge))
> >
> > in nv_ht_enable_msi_mapping, so it seems host_bridge_with_leaf returns
> > true for both. I think because my hw configuration changed a bit
> > (inserted one PCIe card) comparing to last time I tested old v4 version,
> > this doesn't work anymore - so the leaf check alone is not realiable, I
> > guess. For me adding something like this, makes it work: (I hope the
> > description makes sense, as I am just refering to the function names and
> > trying to guess its meanings.)
> >
> > Patch is against linux-next branch of pci tree.
> >
> > [patch] pci: enable MSI on host bridge without checking for leaves
> >
> > On C51 the host bridge needs to be enabled, but the MCP51 host bridge
> > not. So don't check for leaves on the main host bridge.
> >
> > Signed-off-by: Prakash Punnoor <prakash@punnoor.de>
> >
> > --- drivers/pci/quirks.c.old    2009-03-28 14:06:07.249250095 +0100
> > +++ drivers/pci/quirks.c        2009-03-28 14:22:35.027510230 +0100
> > @@ -2292,8 +2292,10 @@ static void __devinit __nv_msi_ht_cap_qu
> >         if (pos != 0) {
> >                 /* Host bridge is to HT */
> >                 if (found == 1) {
> > -                       /* it is not enabled, try to enable it */
> > -                       if (all)
> > +                       /* it is not enabled, try to enable it;
> > +                        * don't check for leaves on host bridge
> > +                        */
> > +                       if (all || host_bridge->devfn == dev->devfn)
> >                                 ht_enable_msi_mapping(dev);
> >                         else
> >                                 nv_ht_enable_msi_mapping(dev);
>
> seems it is not right, it may enable your 09.0 again.

No if you look into the whole function, you'll see that host_bridge is device 
0:0.  (	host_bridge = pci_get_bus_and_slot(0, PCI_DEVFN(0, 0)); )



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