linux-kernel - Re: [PATCH 3/4]: [PCI]: Add quirk for devices which disable MSI when INTX

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Date:	Wed, 24 Oct 2007 15:30:21 +1000
From:	Michael Ellerman <michael@...erman.id.au>
To:	David Miller <davem@...emloft.net>
Cc:	linux-kernel@...r.kernel.org, jeff@...zik.org,
	barkalow@...ervon.org, linas@...tin.ibm.com,
	chunhao.huang@...mail.com, gregkh@...e.de, htejun@...il.com,
	brice.goglin@...il.com, david.gaarenstroom@...il.com,
	linux-pci@...ey.karlin.mff.cuni.cz, shane.huang@....com,
	linux-ide@...r.kernel.org, brice@...i.com, mchan@...adcom.com
Subject: Re: [PATCH 3/4]: [PCI]: Add quirk for devices which disable MSI
	when INTX_DISABLE is set.

On Tue, 2007-10-23 at 19:53 -0700, David Miller wrote:
> A reasonably common problem with some devices is that they will
> disable MSI generation when the INTX_DISABLE bit is set in the
> PCI_COMMAND register.
> 
> Quirk this explicitly, guarding the pci_intx() calls in msi.c with
> this quirk indication.
> 
> The first entries for this quirk are for 5714 and 5780 Tigon3 chips,
> and thus we can remove the workaround code from the tg3.c driver.
> 
> Signed-off-by: David S. Miller <davem@...emloft.net>

> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 87e0161..a8dd18c 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -237,7 +237,8 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
>  	entry = get_irq_msi(dev->irq);
>  	pos = entry->msi_attrib.pos;
>  
> -	pci_intx(dev, 0);		/* disable intx */
> +	if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
> +		pci_intx(dev, 0); /* disable intx */
>  	msi_set_enable(dev, 0);
>  	write_msi_msg(dev->irq, &entry->msg);
>  	if (entry->msi_attrib.maskbit)
> @@ -260,7 +261,8 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
>  		return;
>  
>  	/* route the table */
> -	pci_intx(dev, 0);		/* disable intx */
> +	if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
> +		pci_intx(dev, 0); /* disable intx */
>  	msix_set_enable(dev, 0);
>  
>  	list_for_each_entry(entry, &dev->msi_list, list) {
> @@ -343,7 +345,8 @@ static int msi_capability_init(struct pci_dev *dev)
>  	}
>  
>  	/* Set MSI enabled bits	 */
> -	pci_intx(dev, 0);		/* disable intx */
> +	if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
> +		pci_intx(dev, 0); /* disable intx */
>  	msi_set_enable(dev, 1);
>  	dev->msi_enabled = 1;
>  
> @@ -433,7 +436,8 @@ static int msix_capability_init(struct pci_dev *dev,
>  		i++;
>  	}
>  	/* Set MSI-X enabled bits */
> -	pci_intx(dev, 0);		/* disable intx */
> +	if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
> +		pci_intx(dev, 0); /* disable intx */
>  	msix_set_enable(dev, 1);
>  	dev->msix_enabled = 1;
>  
> @@ -528,7 +532,8 @@ void pci_disable_msi(struct pci_dev* dev)
>  		return;
>  
>  	msi_set_enable(dev, 0);
> -	pci_intx(dev, 1);		/* enable intx */
> +	if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
> +		pci_intx(dev, 1); /* enable intx */
>  	dev->msi_enabled = 0;
>  
>  	BUG_ON(list_empty(&dev->msi_list));
> @@ -640,7 +645,8 @@ void pci_disable_msix(struct pci_dev* dev)
>  		return;
>  
>  	msix_set_enable(dev, 0);
> -	pci_intx(dev, 1);		/* enable intx */
> +	if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
> +		pci_intx(dev, 1); /* enable intx */
>  	dev->msix_enabled = 0;
>  
>  	msix_free_all_irqs(dev);


That looks like 6 hunks doing exactly the same thing? What about
creating a pci_intx_quirked() (or something) that checks the flag and
then does/or does not call pci_intx().

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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