From: Alan Stern <stern@rowland.harvard.edu>
To: Hannes Reinecke <hare@suse.de>
Cc: linux-usb@vger.kernel.org, <linux-kernel@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Oliver Neukum <oneukum@suse.de>, Thomas Renninger <trenn@suse.de>,
Yinghai Lu <yinghai@kernel.org>,
Frederik Himpe <fhimpe@vub.ac.be>,
David Haerdeman <david@hardeman.nu>
Subject: Re: [PATCH] usb: correctly enable interrupts for xhci
Date: Fri, 1 Mar 2013 09:54:42 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1303010951100.1534-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <1362127974-24487-1-git-send-email-hare@suse.de>
On Fri, 1 Mar 2013, Hannes Reinecke wrote:
> xhci might run with MSI/MSI-X only, with no support for legacy
> interrupts. On these devices the request_irq() call in usb_add_hcd()
> will fail, causing the entire device to fail.
> For xhci this is especially painful as the driver will enable
> interrupts during xhci_run(), so the initial call to request_irq()
> is not required anyway.
>
> This patch adds a flag 'msix_supported' to struct usb_hcd, which
> will cause usb_add_hcd() to skip interrupt setup. This flag is
> set in xhci-pci, so the registration will skip the first request_irq()
> and can proceed.
I think it might be better to fix this in hcd-pci.c:usb_hcd_pci_probe.
At that point if we see that MSI/MSI-X is available, the call to
usb_add_hcd can pass 0 instead of dev->irq.
It may even be possible to do this without adding an extra flag
anywhere. It also has the advantage of keeping special knowledge about
MSI encapsulated in the PCI-specific parts of the code.
Alan Stern
prev parent reply other threads:[~2013-03-01 14:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-01 8:52 [PATCH] usb: correctly enable interrupts for xhci Hannes Reinecke
2013-03-01 10:53 ` David Härdeman
2013-03-01 14:54 ` Alan Stern [this message]
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