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, 13 deletions

diff --git a/sys/dev/mps/mps_pci.c b/sys/dev/mps/mps_pci.c
index e64acdc..5417ae6 100644
--- a/sys/dev/mps/mps_pci.c
+++ b/sys/dev/mps/mps_pci.c
@@ -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);