From: Jay Lubomirski <jaylubo@motorola.com>
Date: Wed, 27 Jun 2007 21:10:09 +0000 (-0700)
Subject: [PATCH] serial: clear proper MPSC interrupt cause bits
X-Git-Tag: v2.6.20.16~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=602f7345ec777e44da80a06b60aabd1245509428;p=thirdparty%2Fkernel%2Fstable.git

[PATCH] serial: clear proper MPSC interrupt cause bits

The interrupt clearing code in mpsc_sdma_intr_ack() mistakenly clears the
interrupt for both controllers instead of just the one its supposed to.
This can result in the other controller appearing to hang because its
interrupt was effectively lost.

So, don't clear the interrupt cause bits for both MPSC controllers when
clearing the interrupt for one of them.  Just clear the one that is
supposed to be cleared.

Signed-off-by: Jay Lubomirski <jaylubo@motorola.com>
Acked-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/serial/mpsc.c b/drivers/serial/mpsc.c
index 3d2fcc57b1ced..64ed5ef5a612f 100644
--- a/drivers/serial/mpsc.c
+++ b/drivers/serial/mpsc.c
@@ -502,7 +502,8 @@ mpsc_sdma_intr_ack(struct mpsc_port_info *pi)
 
 	if (pi->mirror_regs)
 		pi->shared_regs->SDMA_INTR_CAUSE_m = 0;
-	writel(0, pi->shared_regs->sdma_intr_base + SDMA_INTR_CAUSE);
+	writeb(0x00, pi->shared_regs->sdma_intr_base + SDMA_INTR_CAUSE +
+	       pi->port.line);
 	return;
 }