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ahci: only try to use multi-MSI mode if there is more than 1 port

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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: 0b9e2988 ("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>
This commit is contained in:
Christoph Hellwig 2016-10-18 09:00:52 +02:00 committed by Tejun Heo
parent 1001354ca3
commit 17a51f12cf
1 changed files with 17 additions and 14 deletions
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31
drivers/ata/ahci.c
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@ -1418,21 +1418,24 @@ static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
* Message mode could be enforced. In this case assume that advantage * Message mode could be enforced. In this case assume that advantage
* of multipe MSIs is negated and use single MSI mode instead. * of multipe MSIs is negated and use single MSI mode instead.
*/ */
nvec = pci_alloc_irq_vectors(pdev, n_ports, INT_MAX, if (n_ports > 1) {
PCI_IRQ_MSIX | PCI_IRQ_MSI); nvec = pci_alloc_irq_vectors(pdev, n_ports, INT_MAX,
if (nvec > 0) { PCI_IRQ_MSIX | PCI_IRQ_MSI);
if (!(readl(hpriv->mmio + HOST_CTL) & HOST_MRSM)) { if (nvec > 0) {
hpriv->get_irq_vector = ahci_get_irq_vector; if (!(readl(hpriv->mmio + HOST_CTL) & HOST_MRSM)) {
hpriv->flags |= AHCI_HFLAG_MULTI_MSI; hpriv->get_irq_vector = ahci_get_irq_vector;
return nvec; hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
} return nvec;
}
/* /*
* Fallback to single MSI mode if the controller enforced MRSM * Fallback to single MSI mode if the controller
* mode. * enforced MRSM mode.
*/ */
printk(KERN_INFO "ahci: MRSM is on, fallback to single MSI\n"); printk(KERN_INFO
pci_free_irq_vectors(pdev); "ahci: MRSM is on, fallback to single MSI\n");
pci_free_irq_vectors(pdev);
}
} }
/* /*