[PATCH] hw/char/pl011: fix receiving multiple chars

[PATCH] hw/char/pl011: fix receiving multiple chars

[Zack Marvel]

When using the GTK UI with libvte, multicharacter keystrokes are not
sent correctly (such as arrow keys). This is not an issue for e.g. the
SDL UI because qemu_chr_be_write is called with len=1 for each character
(SDL sends more than once keystroke).

Buglink: https://bugs.launchpad.net/qemu/+bug/1407808

Signed-off-by: Zack Marvel <zpmarvel@gmail.com>
---
 hw/char/pl011.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/char/pl011.c b/hw/char/pl011.c
index ea4a4e5235..2ea8fd2685 100644
--- a/hw/char/pl011.c
+++ b/hw/char/pl011.c
@@ -300,7 +300,9 @@ static void pl011_put_fifo(void *opaque, uint32_t value)
 
 static void pl011_receive(void *opaque, const uint8_t *buf, int size)
 {
-    pl011_put_fifo(opaque, *buf);
+    for (int i = 0; i < size; i++) {
+        pl011_put_fifo(opaque, buf[i]);
+    }
 }
 
 static void pl011_event(void *opaque, QEMUChrEvent event)
-- 
2.20.1

Re: [PATCH] hw/char/pl011: fix receiving multiple chars

[Peter Maydell]

On Sun, 21 Feb 2021 at 15:04, Zack Marvel <zpmarvel@gmail.com> wrote:
>
> When using the GTK UI with libvte, multicharacter keystrokes are not
> sent correctly (such as arrow keys). This is not an issue for e.g. the
> SDL UI because qemu_chr_be_write is called with len=1 for each character
> (SDL sends more than once keystroke).
>
> Buglink: https://bugs.launchpad.net/qemu/+bug/1407808
>
> Signed-off-by: Zack Marvel <zpmarvel@gmail.com>

> @@ -300,7 +300,9 @@ static void pl011_put_fifo(void *opaque, uint32_t value)
>
>  static void pl011_receive(void *opaque, const uint8_t *buf, int size)
>  {
> -    pl011_put_fifo(opaque, *buf);
> +    for (int i = 0; i < size; i++) {
> +        pl011_put_fifo(opaque, buf[i]);
> +    }
>  }

I think this is a bug in whatever is on the other end
of the chardev connection. The pl011 can_receive routine
only ever returns 0 or 1, so it is an error for the
code calling its receive function to ever pass a
size that is greater than 1.

thanks
-- PMM

Re: [PATCH] hw/char/pl011: fix receiving multiple chars

[Zack Marvel]

Peter,

Thanks for the quick review. You're right, I misunderstood the API and 
the bug is in ui/gtk.c.

Thanks,
Zack M

On 2/21/21 8:19 AM, Peter Maydell wrote:
> On Sun, 21 Feb 2021 at 15:04, Zack Marvel <zpmarvel@gmail.com> wrote:
>>
>> When using the GTK UI with libvte, multicharacter keystrokes are not
>> sent correctly (such as arrow keys). This is not an issue for e.g. the
>> SDL UI because qemu_chr_be_write is called with len=1 for each character
>> (SDL sends more than once keystroke).
>>
>> Buglink: https://bugs.launchpad.net/qemu/+bug/1407808
>>
>> Signed-off-by: Zack Marvel <zpmarvel@gmail.com>
> 
>> @@ -300,7 +300,9 @@ static void pl011_put_fifo(void *opaque, uint32_t value)
>>
>>   static void pl011_receive(void *opaque, const uint8_t *buf, int size)
>>   {
>> -    pl011_put_fifo(opaque, *buf);
>> +    for (int i = 0; i < size; i++) {
>> +        pl011_put_fifo(opaque, buf[i]);
>> +    }
>>   }
> 
> I think this is a bug in whatever is on the other end
> of the chardev connection. The pl011 can_receive routine
> only ever returns 0 or 1, so it is an error for the
> code calling its receive function to ever pass a
> size that is greater than 1.
> 
> thanks
> -- PMM
>