[RFC, PATCH] pcmcia/yenta: don't mess with bridge control register

[Daniel Ritz]

hi there

please give this one some testing. if it doesn't show negative effect it'll
go to akpm soooon.

rgds
-daniel

----

[PATCH] pcmcia/yenta: don't mess with bridge control register

in interrupt probing (both ISA and PCI) the bridge control register is used to
change interrupt routing to ISA or PCI by changing bit 7. but this bit only
controls the routing of card functional interrupts, not the CSC interrupts
which are used for interrupt probing.
a bad side effect of messing with this register in yenta_probe_irq() is that
it can lead to irq storms if a card is inserted and already powered by the
BIOS.
usage in yenta_sock_init() and yenta_config_init() seem to be fishy as well.

Signed-off-by: Daniel Ritz <daniel.ritz at gmx.ch>

---
diff --git a/drivers/pcmcia/yenta_socket.c b/drivers/pcmcia/yenta_socket.c
--- a/drivers/pcmcia/yenta_socket.c
+++ b/drivers/pcmcia/yenta_socket.c
@@ -489,12 +489,6 @@ static void yenta_interrogate(struct yen
 static int yenta_sock_init(struct pcmcia_socket *sock)
 {
 	struct yenta_socket *socket = container_of(sock, struct yenta_socket, socket);
-	u16 bridge;
-
-	bridge = config_readw(socket, CB_BRIDGE_CONTROL) & ~CB_BRIDGE_INTR;
-	if (!socket->cb_irq)
-		bridge |= CB_BRIDGE_INTR;
-	config_writew(socket, CB_BRIDGE_CONTROL, bridge);
 
 	exca_writeb(socket, I365_GBLCTL, 0x00);
 	exca_writeb(socket, I365_GENCTL, 0x00);
@@ -814,16 +808,8 @@ static unsigned int yenta_probe_irq(stru
 {
 	int i;
 	unsigned long val;
-	u16 bridge_ctrl;
 	u32 mask;
 
-	/* Set up ISA irq routing to probe the ISA irqs.. */
-	bridge_ctrl = config_readw(socket, CB_BRIDGE_CONTROL);
-	if (!(bridge_ctrl & CB_BRIDGE_INTR)) {
-		bridge_ctrl |= CB_BRIDGE_INTR;
-		config_writew(socket, CB_BRIDGE_CONTROL, bridge_ctrl);
-	}
-
 	/*
 	 * Probe for usable interrupts using the force
 	 * register to generate bogus card status events.
@@ -845,9 +831,6 @@ static unsigned int yenta_probe_irq(stru
 
 	mask = probe_irq_mask(val) & 0xffff;
 
-	bridge_ctrl &= ~CB_BRIDGE_INTR;
-	config_writew(socket, CB_BRIDGE_CONTROL, bridge_ctrl);
-
 	return mask;
 }
 
@@ -875,18 +858,11 @@ static irqreturn_t yenta_probe_handler(i
 /* probes the PCI interrupt, use only on override functions */
 static int yenta_probe_cb_irq(struct yenta_socket *socket)
 {
-	u16 bridge_ctrl;
-
 	if (!socket->cb_irq)
 		return -1;
 
 	socket->probe_status = 0;
 
-	/* disable ISA interrupts */
-	bridge_ctrl = config_readw(socket, CB_BRIDGE_CONTROL);
-	bridge_ctrl &= ~CB_BRIDGE_INTR;
-	config_writew(socket, CB_BRIDGE_CONTROL, bridge_ctrl);
-
 	if (request_irq(socket->cb_irq, yenta_probe_handler, SA_SHIRQ, "yenta", socket)) {
 		printk(KERN_WARNING "Yenta: request_irq() in yenta_probe_cb_irq() failed!\n");
 		return -1;
@@ -897,7 +873,7 @@ static int yenta_probe_cb_irq(struct yen
 	cb_writel(socket, CB_SOCKET_EVENT, -1);
 	cb_writel(socket, CB_SOCKET_MASK, CB_CSTSMASK);
 	cb_writel(socket, CB_SOCKET_FORCE, CB_FCARDSTS);
-	
+
 	msleep(100);
 
 	/* disable interrupts */
@@ -962,8 +938,8 @@ static void yenta_config_init(struct yen
 	 *  - PCI interrupts enabled if a PCI interrupt exists..
 	 */
 	bridge = config_readw(socket, CB_BRIDGE_CONTROL);
-	bridge &= ~(CB_BRIDGE_CRST | CB_BRIDGE_PREFETCH1 | CB_BRIDGE_INTR | CB_BRIDGE_ISAEN | CB_BRIDGE_VGAEN);
-	bridge |= CB_BRIDGE_PREFETCH0 | CB_BRIDGE_POSTEN | CB_BRIDGE_INTR;
+	bridge &= ~(CB_BRIDGE_CRST | CB_BRIDGE_PREFETCH1 | CB_BRIDGE_ISAEN | CB_BRIDGE_VGAEN);
+	bridge |= CB_BRIDGE_PREFETCH0 | CB_BRIDGE_POSTEN;
 	config_writew(socket, CB_BRIDGE_CONTROL, bridge);
 }