Messages in this thread Patch in this message | | | Date | Wed, 15 Nov 2006 11:49:28 -0800 | From | Stephen Hemminger <> | Subject | Re: [PATCH] ALSA: hda-intel - Disable MSI support by default |
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On Wed, 15 Nov 2006 14:23:20 -0500 Jeff Garzik <jeff@garzik.org> wrote:
> Stephen Hemminger wrote: > > On Tue, 14 Nov 2006 23:24:04 -0500 > > Jeff Garzik <jeff@garzik.org> wrote: > > > >> David Miller wrote: > >>> Is this absolutely true? I've never been sure about this point, and I > >>> was rather convinced after reading various documents that once you > >>> program up the MSI registers to start generating MSI this implicitly > >>> disabled INTX and this was even in the PCI specification. > >>> > >>> It would be great to get a definitive answer on this. > >>> > >>> If it is mandatory, perhaps the driver shouldn't be doing it and > >>> rather the PCI layer MSI enabling should. > > > > pci_enable_msi() calls msi_capability_init() and that disables intx > > already. > [...] > > The driver shouldn't deal with this, pci_disable_msi() does. > > Explicit code reference please? > > AFAICS the PCI layer only touched INTx bit for PCI-Express devices.
Yeah, why is that? Shouldn't it always be adjusting intx. Are there are any MSI capable devices on non-PCI express? Sorry, don't have PCI spec (costs real $$) to check.
--- 2.6.19-rc5.orig/drivers/pci/msi.c 2006-11-15 11:46:23.000000000 -0800 +++ 2.6.19-rc5/drivers/pci/msi.c 2006-11-15 11:46:55.000000000 -0800 @@ -255,10 +255,7 @@ pci_write_config_word(dev, msi_control_reg(pos), control); dev->msix_enabled = 1; } - if (pci_find_capability(dev, PCI_CAP_ID_EXP)) { - /* PCI Express Endpoint device detected */ - pci_intx(dev, 0); /* disable intx */ - } + pci_intx(dev, 0); /* disable intx */ } void disable_msi_mode(struct pci_dev *dev, int pos, int type) @@ -276,10 +273,8 @@ pci_write_config_word(dev, msi_control_reg(pos), control); dev->msix_enabled = 0; } - if (pci_find_capability(dev, PCI_CAP_ID_EXP)) { - /* PCI Express Endpoint device detected */ - pci_intx(dev, 1); /* enable intx */ - } + + pci_intx(dev, 1); /* re-enable intx */ } static int msi_lookup_irq(struct pci_dev *dev, int type)
-- Stephen Hemminger <shemminger@osdl.org> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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