diff options
| author | Hendrik Brueckner <brueckner@linux.vnet.ibm.com> | 2011-07-05 21:50:18 +0000 |
|---|---|---|
| committer | Jonas ABERG <jonas.aberg@stericsson.com> | 2011-10-28 11:15:43 +0200 |
| commit | e879ff3ef1ee6d3d92f8dafea79983493572f43b (patch) | |
| tree | b474994817bb4886c3113cc05d08d07b9df83fa0 | |
| parent | 46443ef544c5f25f10f6673afe35368ac57c1543 (diff) | |
hvc_console: Improve tty/console put_chars handling
commit 8c2381af0d3ef62a681dac5a141b6dabb27bf2e1 upstream.
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 <brueckner@linux.vnet.ibm.com>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Change-Id: I475d5ab252ac3fecbf7c5f12f0f71a738e944ee9
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/35668
Tested-by: Per VAHLNE <per.xx.vahlne@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
| -rw-r--r-- | drivers/tty/hvc/hvc_console.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c index e9cba13ee80..aa84555048b 100644 --- a/drivers/tty/hvc/hvc_console.c +++ b/drivers/tty/hvc/hvc_console.c @@ -163,8 +163,10 @@ static void hvc_console_print(struct console *co, const char *b, } 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 *hp) 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; } |