2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Hendrik Brueckner <[email protected]> [ upstream commit 8c2381af0d3ef62a681dac5a141b6dabb27bf2e1 ] Currently, the hvc_console_print() function drops console output if the hvc backend's put_chars() returns 0. This patch changes this behavior to allow a retry through returning -EAGAIN. This change also affects the hvc_push() function. Both functions are changed to handle -EAGAIN and to retry the put_chars() operation. If a hvc backend returns -EAGAIN, the retry handling differs: - hvc_console_print() spins to write the complete console output. - hvc_push() behaves the same way as for returning 0. Now hvc backends can indirectly control the way how console output is handled through the hvc console layer. Signed-off-by: Hendrik Brueckner <[email protected]> Acked-by: Anton Blanchard <[email protected]> Cc: <[email protected]> Signed-off-by: Benjamin Herrenschmidt <[email protected]> Signed-off-by: Andi Kleen <[email protected]> Index: linux-2.6.35.y/drivers/char/hvc_console.c =================================================================== --- linux-2.6.35.y.orig/drivers/char/hvc_console.c +++ linux-2.6.35.y/drivers/char/hvc_console.c @@ -163,8 +163,10 @@ static void hvc_console_print(struct con } else { r = cons_ops[index]->put_chars(vtermnos[index], c, i); if (r <= 0) { - /* throw away chars on error */ - i = 0; + /* throw away characters on error + * but spin in case of -EAGAIN */ + if (r != -EAGAIN) + i = 0; } else if (r > 0) { i -= r; if (i > 0) @@ -448,7 +450,7 @@ static int hvc_push(struct hvc_struct *h n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); if (n <= 0) { - if (n == 0) { + if (n == 0 || n == -EAGAIN) { hp->do_wakeup = 1; return 0; } _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
