ide-cd: fix 'ireason' reporting in cdrom_pc_intr()

Mask 'ireason' variable so only the valid interrupt reason bits
will be reported on "drive appears confused" error.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index 522580f29ddc..c7d77f0ad892 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -1446,7 +1446,7 @@ static ide_startstop_t cdrom_pc_intr (ide_drive_t *drive)
                 return ide_stopped;
 
         /* Read the interrupt reason and the transfer length. */
-        ireason = HWIF(drive)->INB(IDE_IREASON_REG);
+        ireason = HWIF(drive)->INB(IDE_IREASON_REG) & 0x3;
         lowcyl  = HWIF(drive)->INB(IDE_BCOUNTL_REG);
         highcyl = HWIF(drive)->INB(IDE_BCOUNTH_REG);
 
@@ -1487,7 +1487,7 @@ static ide_startstop_t cdrom_pc_intr (ide_drive_t *drive)
         if (thislen > len) thislen = len;
 
         /* The drive wants to be written to. */
-        if ((ireason & 3) == 0) {
+        if (ireason == 0) {
                 if (!rq->data) {
                         blk_dump_rq_flags(rq, "cdrom_pc_intr, write");
                         goto confused;
@@ -1509,7 +1509,7 @@ static ide_startstop_t cdrom_pc_intr (ide_drive_t *drive)
         }
 
         /* Same drill for reading. */
-        else if ((ireason & 3) == 2) {
+        else if (ireason == 2) {
                 if (!rq->data) {
                         blk_dump_rq_flags(rq, "cdrom_pc_intr, read");
                         goto confused;