ALSA: au88x0: Fix calculation in vortex_wtdma_bufshift()

commit 62db7152c924e4c060e42b34a69cd39658e8a0dc upstream.

vortex_wtdma_bufshift() function does calculate the page index
wrongly, first masking then shift, which always results in zero.
The proper computation is to first shift, then mask.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/sound/pci/au88x0/au88x0_core.c b/sound/pci/au88x0/au88x0_core.c
index 4891503..dd6e74f 100644 (file)
--- a/sound/pci/au88x0/au88x0_core.c
+++ b/sound/pci/au88x0/au88x0_core.c
@@ -1444,9 +1444,8 @@ static int vortex_wtdma_bufshift(vortex_t * vortex, int wtdma)
        int page, p, pp, delta, i;
 
        page =
-           (hwread(vortex->mmio, VORTEX_WTDMA_STAT + (wtdma << 2)) &
-            WT_SUBBUF_MASK)
-           >> WT_SUBBUF_SHIFT;
+           (hwread(vortex->mmio, VORTEX_WTDMA_STAT + (wtdma << 2))
+            >> WT_SUBBUF_SHIFT) & WT_SUBBUF_MASK;
        if (dma->nr_periods >= 4)
                delta = (page - dma->period_real) & 3;
        else {