Date: Thu, 27 Feb 2014 13:30:02 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org Cc: Ryan Stone <rysto32@gmail.com> Subject: Re: [PATCH] Add MSI support to puc(9) Message-ID: <201402271330.02699.jhb@freebsd.org> In-Reply-To: <CAFMmRNy9EG3byRV1b=4W5MejMiAz8yV6UnnEMjcJmY-FyMj2sg@mail.gmail.com> References: <CAFMmRNy9EG3byRV1b=4W5MejMiAz8yV6UnnEMjcJmY-FyMj2sg@mail.gmail.com>
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On Wednesday, February 26, 2014 2:22:48 pm Ryan Stone wrote: > The Exar XR17V358 is a PCIe device and it supports a single MSI > interrupt. This patch will make puc(9) use an MSI interrupt on > devices that declare that they support it: > > http://people.freebsd.org/~rstone/patches/puc_msi.diff > > This patch may be overly paranoid; I was worried that it's wasn't > guaranteed that I could always call pci_alloc_msi() (forgetting that > the P in puc stands for PCI) so I added a new puc_cfg_cmd that > individual device config methods could implement to advertise support > rather than depending on pci_alloc_msi() to behave sanely. > > I have tested the patch on both a XR17V358 and a XR17V258 (which is a > legacy PCI device that does not support PCI) I would suggest reworking this so that you try MSI for all PCI devices. I would do this by removing the 'sc_irid = 0' from puc_bfe_attach() so that it can be set by callers. You could then add attach/detach routines in puc_pci.c that use pci_alloc_msi() and set sc_irid to 1 if MSI works. The sc_irid value would also work as a flag for knowing if detach needs to call pci_release_msi() (or puc_pci_attach() handling failure in puc_bfe_attach()) (though I wouldn't be opposed to keeping sc_msi as a separate flag). -- John Baldwin
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