ahci: only try to use multi-MSI mode if there is more than 1 port (17a51f12) · Commits · 戴 / test

We should only try to allocate multiple MSI or MSI-X vectors if the device actually has multiple ports. Otherwise pci_alloc_irq_vectors will return a single vector due to n_ports = 1, in which case we shouldn't set the AHCI_HFLAG_MULTI_MSI flag. Signed-off-by:

Christoph Hellwig <hch@lst.de> Fixes: ("ahci: use pci_alloc_irq_vectors") Reported-by:

Emmanuel Benisty <benisty.e@gmail.com> Tested-by:

Emmanuel Benisty <benisty.e@gmail.com> Signed-off-by:

Tejun Heo <tj@kernel.org>

drivers/ata/ahci.c

+17 −14

Original line number	Diff line number	Diff line
		@@ -1418,6 +1418,7 @@ static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
		* Message mode could be enforced. In this case assume that advantage
		* of multipe MSIs is negated and use single MSI mode instead.
		*/
		if (n_ports > 1) {
		nvec = pci_alloc_irq_vectors(pdev, n_ports, INT_MAX,
		PCI_IRQ_MSIX \| PCI_IRQ_MSI);
		if (nvec > 0) {
		@@ -1428,12 +1429,14 @@ static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
		}

		/*
		* Fallback to single MSI mode if the controller enforced MRSM
		* mode.
		* Fallback to single MSI mode if the controller
		* enforced MRSM mode.
		*/
		printk(KERN_INFO "ahci: MRSM is on, fallback to single MSI\n");
		printk(KERN_INFO
		"ahci: MRSM is on, fallback to single MSI\n");
		pci_free_irq_vectors(pdev);
		}
		}

		/*
		* -ENOSPC indicated we don't have enough vectors. Don't bother trying

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