[PATCH] Input: gscps2 - advance receive buffer write index

[PATCH] Input: gscps2 - advance receive buffer write index

[raoxu]

From: Xu Rao <raoxu@uniontech.com>

Commit 44f920069911 ("Input: gscps2 - use guard notation when
acquiring spinlock") moved the receive loop into gscps2_read_data()
and gscps2_report_data().

While moving the code, it preserved the writes to
buffer[ps2port->append], but omitted the following producer index
update from the original loop:

	ps2port->append = (ps2port->append + 1) & BUFFER_SIZE;

As a result, append never advances. Since gscps2_report_data() only
reports bytes while act != append, the receive buffer always appears
empty and no keyboard or mouse data reaches the serio core.

Restore the omitted index update.

Fixes: 44f920069911 ("Input: gscps2 - use guard notation when acquiring spinlock")
Cc: stable@vger.kernel.org # 6.13+
Signed-off-by: Xu Rao <raoxu@uniontech.com>
---
 drivers/input/serio/gscps2.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/input/serio/gscps2.c b/drivers/input/serio/gscps2.c
index 22b2f57..bf9b993 100644
--- a/drivers/input/serio/gscps2.c
+++ b/drivers/input/serio/gscps2.c
@@ -219,6 +219,7 @@ static void gscps2_read_data(struct gscps2port *ps2port)
 		ps2port->buffer[ps2port->append].str = status;
 		ps2port->buffer[ps2port->append].data =
 				gscps2_readb_input(ps2port->addr);
+		ps2port->append = (ps2port->append + 1) & BUFFER_SIZE;
 	} while (true);
 }

--
2.47.3

Re: [PATCH] Input: gscps2 - advance receive buffer write index

[Dmitry Torokhov]

On Wed, Jun 24, 2026 at 05:47:39PM +0800, raoxu wrote:
> From: Xu Rao <raoxu@uniontech.com>
> 
> Commit 44f920069911 ("Input: gscps2 - use guard notation when
> acquiring spinlock") moved the receive loop into gscps2_read_data()
> and gscps2_report_data().
> 
> While moving the code, it preserved the writes to
> buffer[ps2port->append], but omitted the following producer index
> update from the original loop:
> 
> 	ps2port->append = (ps2port->append + 1) & BUFFER_SIZE;
> 
> As a result, append never advances. Since gscps2_report_data() only
> reports bytes while act != append, the receive buffer always appears
> empty and no keyboard or mouse data reaches the serio core.
> 
> Restore the omitted index update.
> 
> Fixes: 44f920069911 ("Input: gscps2 - use guard notation when acquiring spinlock")
> Cc: stable@vger.kernel.org # 6.13+
> Signed-off-by: Xu Rao <raoxu@uniontech.com>

Applied, thank you.

-- 
Dmitry