Date: Fri, 27 Jan 2017 11:28:23 -0800 From: John Baldwin <jhb@freebsd.org> To: Sean Bruno <sbruno@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r312755 - head/sys/net Message-ID: <6817684.C985jk9qCN@ralph.baldwin.cx> In-Reply-To: <201701251437.v0PEb5D7047773@repo.freebsd.org> References: <201701251437.v0PEb5D7047773@repo.freebsd.org>
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On Wednesday, January 25, 2017 02:37:05 PM Sean Bruno wrote: > Author: sbruno > Date: Wed Jan 25 14:37:05 2017 > New Revision: 312755 > URL: https://svnweb.freebsd.org/changeset/base/312755 > > Log: > Add error checking to the pci_find_cap(, PCIY_MSIX,) call that is returns > success and a good value. Only then try to use it and set the MSIX_ENABLE > bit. > > With the current em(4) driver we have observed failures in this case in a > specific environment when pci_find_cap() would not return the assumed > value, which meant we ended up writing to PCI register 2 (PCI_DEVICE_ID) > which is read-only. Why is this writing directly to the MSIX registers at all? pci_alloc_msix() etc. handle those registers for all other drivers and proper suspend/resume depends on drivers using the existing PCI API for managing MSI and MSI-X. > Modified: head/sys/net/iflib.c > ============================================================================== > --- head/sys/net/iflib.c Wed Jan 25 13:42:38 2017 (r312754) > +++ head/sys/net/iflib.c Wed Jan 25 14:37:05 2017 (r312755) > @@ -4779,15 +4783,20 @@ iflib_msix_init(if_ctx_t ctx) > uint16_t pci_cmd_word; > int msix_ctrl, rid; > > - rid = 0; > pci_cmd_word = pci_read_config(dev, PCIR_COMMAND, 2); > pci_cmd_word |= PCIM_CMD_BUSMASTEREN; > pci_write_config(dev, PCIR_COMMAND, pci_cmd_word, 2); This should use 'pci_enable_busmaster()' like other drivers rather than manipulating registers directly. -- John Baldwin
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