Update PCI drivers to no longer look at the MEMIO-enabled bit in the PCI

command register.  The lazy BAR allocation code in FreeBSD sometimes
disables this bit when it detects a range conflict, and will re-enable
it on demand when a driver allocates the BAR.  Thus, the bit is no longer
a reliable indication of capability, and should not be checked.  This
results in the elimination of a lot of code from drivers, and also gives
the opportunity to simplify a lot of drivers to use a helper API to set
the busmaster enable bit.

This changes fixes some recent reports of disk controllers and their
associated drives/enclosures disappearing during boot.

Submitted by:	jhb
Reviewed by:	jfv, marius, achadd, achim
MFC after:	1 day

1 files changed, 1 insertions, 6 deletions

diff --git a/sys/dev/mpt/mpt_pci.c b/sys/dev/mpt/mpt_pci.c
index d6a1d38..74c5292 100644
--- a/sys/dev/mpt/mpt_pci.c
+++ b/sys/dev/mpt/mpt_pci.c
@@ -389,16 +389,11 @@ mpt_pci_attach(device_t dev)
 		/* Print INFO level (if any) if bootverbose is set */
 		mpt->verbose += (bootverbose != 0)? 1 : 0;
 	}
-	/* Make sure memory access decoders are enabled */
-	cmd = pci_read_config(dev, PCIR_COMMAND, 2);
-	if ((cmd & PCIM_CMD_MEMEN) == 0) {
-		device_printf(dev, "Memory accesses disabled");
-		return (ENXIO);
-	}
 
 	/*
 	 * Make sure that SERR, PERR, WRITE INVALIDATE and BUSMASTER are set.
 	 */
+	cmd = pci_read_config(dev, PCIR_COMMAND, 2);
 	cmd |=
 	    PCIM_CMD_SERRESPEN | PCIM_CMD_PERRESPEN |
 	    PCIM_CMD_BUSMASTEREN | PCIM_CMD_MWRICEN;