* [U-Boot] [PATCH] serial: nulldev: Implement "pending" function to fix tstc return "true"
@ 2017-11-03 6:39 Wilson Lee
2017-11-17 15:44 ` [U-Boot] " Tom Rini
0 siblings, 1 reply; 2+ messages in thread
From: Wilson Lee @ 2017-11-03 6:39 UTC (permalink / raw)
To: u-boot
In U-boot, serial_tstc was use to determine is there have a character in
serial console that pending for read. If there is no "pending" function
implemented in serial driver, the serial-uclass will return "true(1)"
to indicate there have a character pending to read.
Thus, read a character from nulldev serial will result in continuous
getting -EAGAIN return which might lead system to hang.
This commit is to fix a bug in nulldev serial which implement "pending"
function in nulldev serial to always indicate there is no character in
console that pending for read.
Signed-off-by: Wilson Lee <wilson.lee@ni.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Keng Soon Cheah <keng.soon.cheah@ni.com>
Cc: Chen Yee Chew <chen.yee.chew@ni.com>
Cc: Bin Meng <bmeng.cn@gmail.com>
---
drivers/serial/serial_nulldev.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/serial/serial_nulldev.c b/drivers/serial/serial_nulldev.c
index 0768308..17b2310 100644
--- a/drivers/serial/serial_nulldev.c
+++ b/drivers/serial/serial_nulldev.c
@@ -18,6 +18,11 @@ static int nulldev_serial_getc(struct udevice *dev)
return -EAGAIN;
}
+static int nulldev_serial_pending(struct udevice *dev, bool input)
+{
+ return 0;
+}
+
static int nulldev_serial_input(struct udevice *dev)
{
return 0;
@@ -36,6 +41,7 @@ static const struct udevice_id nulldev_serial_ids[] = {
const struct dm_serial_ops nulldev_serial_ops = {
.putc = nulldev_serial_putc,
+ .pending = nulldev_serial_pending,
.getc = nulldev_serial_getc,
.setbrg = nulldev_serial_setbrg,
};
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [U-Boot] serial: nulldev: Implement "pending" function to fix tstc return "true"
2017-11-03 6:39 [U-Boot] [PATCH] serial: nulldev: Implement "pending" function to fix tstc return "true" Wilson Lee
@ 2017-11-17 15:44 ` Tom Rini
0 siblings, 0 replies; 2+ messages in thread
From: Tom Rini @ 2017-11-17 15:44 UTC (permalink / raw)
To: u-boot
On Thu, Nov 02, 2017 at 11:39:51PM -0700, Wilson Lee wrote:
> In U-boot, serial_tstc was use to determine is there have a character in
> serial console that pending for read. If there is no "pending" function
> implemented in serial driver, the serial-uclass will return "true(1)"
> to indicate there have a character pending to read.
>
> Thus, read a character from nulldev serial will result in continuous
> getting -EAGAIN return which might lead system to hang.
>
> This commit is to fix a bug in nulldev serial which implement "pending"
> function in nulldev serial to always indicate there is no character in
> console that pending for read.
>
> Signed-off-by: Wilson Lee <wilson.lee@ni.com>
> Cc: Joe Hershberger <joe.hershberger@ni.com>
> Cc: Keng Soon Cheah <keng.soon.cheah@ni.com>
> Cc: Chen Yee Chew <chen.yee.chew@ni.com>
> Cc: Bin Meng <bmeng.cn@gmail.com>
Applied to u-boot/master, thanks!
--
Tom
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2017-11-03 6:39 [U-Boot] [PATCH] serial: nulldev: Implement "pending" function to fix tstc return "true" Wilson Lee
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