[PATCH] Fix Specialix SX corruption

[Marc Zyngier <maz@misterjones.org>]

Roger,

With the latest kernels, I experienced some strange corruption, some
'*****' being randomly inserted in the character flow, like this:

ashes:~#
ashes:~#
a*******shes:~#
ashes:~#
ashes:~#

Further investigation shows that the problem was introduced during
Alan's "TTY layer buffering revamp" patch, the amount of data to be
copied being reduced after buffer allocation. Moving the count fixup
around solves the problem.

Patch against v2.6.16-rc5.

Signed-off-by: Marc Zyngier <maz@misterjones.org>

diff --git a/drivers/char/sx.c b/drivers/char/sx.c
index 588e75e..a6b4f02 100644
--- a/drivers/char/sx.c
+++ b/drivers/char/sx.c
@@ -1095,17 +1095,17 @@ static inline void sx_receive_chars (str
 
 		sx_dprintk (SX_DEBUG_RECEIVE, "rxop=%d, c = %d.\n", rx_op, c); 
 
+		/* Don't copy past the end of the hardware receive buffer */
+		if (rx_op + c > 0x100) c = 0x100 - rx_op;
+
+		sx_dprintk (SX_DEBUG_RECEIVE, "c = %d.\n", c);
+
 		/* Don't copy more bytes than there is room for in the buffer */
 
 		c = tty_prepare_flip_string(tty, &rp, c);
 
 		sx_dprintk (SX_DEBUG_RECEIVE, "c = %d.\n", c); 
 
-		/* Don't copy past the end of the hardware receive buffer */
-		if (rx_op + c > 0x100) c = 0x100 - rx_op;
-
-		sx_dprintk (SX_DEBUG_RECEIVE, "c = %d.\n", c);
-
 		/* If for one reason or another, we can't copy more data, we're done! */
 		if (c == 0) break;
 

-- 
And if you don't know where you're going, any road will take you there...
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/