During the initialisation that driver uses a buffer on the stack
for DMA. That violates the cache coherency rules. The fix is to
allocate the buffer with kmalloc().

Signed-off-by: Oliver Neukum <oneu...@suse.com>
---
 drivers/input/touchscreen/sur40.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/input/touchscreen/sur40.c 
b/drivers/input/touchscreen/sur40.c
index d214f22..5581954 100644
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -196,29 +196,32 @@ static int sur40_command(struct sur40_state *dev,
 /* Initialization routine, called from sur40_open */
 static int sur40_init(struct sur40_state *dev)
 {
-       int result;
-       u8 buffer[24];
+       int result = -ENOMEM;
+       u8 *buffer;
 
+       buffer = kmalloc(24, GFP_KERNEL);
+       if (!buffer)
+               goto error;
        /* stupidly replay the original MS driver init sequence */
        result = sur40_command(dev, SUR40_GET_VERSION, 0x00, buffer, 12);
        if (result < 0)
-               return result;
+               goto error;
 
        result = sur40_command(dev, SUR40_GET_VERSION, 0x01, buffer, 12);
        if (result < 0)
-               return result;
+               goto error;
 
        result = sur40_command(dev, SUR40_GET_VERSION, 0x02, buffer, 12);
        if (result < 0)
-               return result;
+               goto error;
 
        result = sur40_command(dev, SUR40_UNKNOWN2,    0x00, buffer, 24);
        if (result < 0)
-               return result;
+               goto error;
 
        result = sur40_command(dev, SUR40_UNKNOWN1,    0x00, buffer,  5);
        if (result < 0)
-               return result;
+               goto error;
 
        result = sur40_command(dev, SUR40_GET_VERSION, 0x03, buffer, 12);
 
@@ -226,7 +229,8 @@ static int sur40_init(struct sur40_state *dev)
         * Discard the result buffer - no known data inside except
         * some version strings, maybe extract these sometime...
         */
-
+error:
+       kfree(buffer);
        return result;
 }
 
-- 
2.1.4

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