kern/181148: [ata] sas expanders not available in 9.2-RC1 [regression]
Christopher D. Harrison
harrison at biostat.wisc.edu
Fri Aug 9 18:20:02 UTC 2013
The following reply was made to PR kern/181148; it has been noted by GNATS.
From: "Christopher D. Harrison" <harrison at biostat.wisc.edu>
To: John Baldwin <jhb at freebsd.org>
Cc: bug-followup at freebsd.org, scottl at freebsd.org,
Doug White <dwhite at freebsd.org>
Subject: Re: kern/181148: [ata] sas expanders not available in 9.2-RC1
[regression]
Date: Fri, 09 Aug 2013 13:15:23 -0500
I upgraded the bios and it appears that this fixed the issue. I wish I
had a board running the old bios version now to test this new code.
Thanks for all your help in debugging this issue.
-C
On 08/09/13 13:05, John Baldwin wrote:
> The mps(4) driver is just broken. 9.2 includes a fix that if your BIOS
> writers can't do simple math and allocate conflicting resources, it disables
> decoding of the device where it finds the conflict. Later if a device driver
> expicitly asks to use that resource, the PCI bus will allocate a fresh
> resource range that doesn't conflict if possible. If it suceeds it re-enables
> decoding. The mps(4) driver checks to see if decoding is enabled before it
> calls bus_alloc_resource(). It should not. It should assume that if
> bus_alloc_resource() succeeds, everything is fine and decoding will be
> enabled. Try this fix:
>
> Index: mps_pci.c
> ===================================================================
> --- mps_pci.c (revision 254147)
> +++ mps_pci.c (working copy)
> @@ -183,7 +183,6 @@ mps_pci_attach(device_t dev)
> {
> struct mps_softc *sc;
> struct mps_ident *m;
> - uint16_t command;
> int error;
>
> sc = device_get_softc(dev);
> @@ -193,18 +192,7 @@ mps_pci_attach(device_t dev)
> sc->mps_flags = m->flags;
>
> /* Twiddle basic PCI config bits for a sanity check */
> - command = pci_read_config(dev, PCIR_COMMAND, 2);
> - command |= PCIM_CMD_BUSMASTEREN;
> - pci_write_config(dev, PCIR_COMMAND, command, 2);
> - command = pci_read_config(dev, PCIR_COMMAND, 2);
> - if ((command& PCIM_CMD_BUSMASTEREN) == 0) {
> - mps_printf(sc, "Cannot enable PCI busmaster\n");
> - return (ENXIO);
> - }
> - if ((command& PCIM_CMD_MEMEN) == 0) {
> - mps_printf(sc, "PCI memory window not available\n");
> - return (ENXIO);
> - }
> + pci_enable_busmaster(dev);
>
> /* Allocate the System Interface Register Set */
> sc->mps_regs_rid = PCIR_BAR(1);
>
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