On Sun, Mar 21, 2021 at 08:53:40PM -0700, Dmitry Torokhov wrote:
> Given that all serio drivers except one implement write() method
> let's make it mandatory to avoid testing for its presence whenever
> we attempt to use it.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> ---
> drivers/input/serio/ams_delta_serio.c | 6 ++++++
> drivers/input/serio/serio.c | 5 +++++
> include/linux/serio.h | 5 +----
> 3 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/input/serio/ams_delta_serio.c b/drivers/input/serio/ams_delta_serio.c
> index 1c0be299f179..a1c314897951 100644
> --- a/drivers/input/serio/ams_delta_serio.c
> +++ b/drivers/input/serio/ams_delta_serio.c
> @@ -89,6 +89,11 @@ static irqreturn_t ams_delta_serio_interrupt(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> +static int ams_delta_serio_write(struct serio *serio, u8 data)
> +{
> + return -EINVAL;
> +}
> +
> static int ams_delta_serio_open(struct serio *serio)
> {
> struct ams_delta_serio *priv = serio->port_data;
> @@ -157,6 +162,7 @@ static int ams_delta_serio_init(struct platform_device *pdev)
> priv->serio = serio;
>
> serio->id.type = SERIO_8042;
> + serio->write = ams_delta_serio_write;
> serio->open = ams_delta_serio_open;
> serio->close = ams_delta_serio_close;
> strlcpy(serio->name, "AMS DELTA keyboard adapter", sizeof(serio->name));
> diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
> index 29f491082926..8d229a11bb6b 100644
> --- a/drivers/input/serio/serio.c
> +++ b/drivers/input/serio/serio.c
> @@ -694,6 +694,11 @@ EXPORT_SYMBOL(serio_reconnect);
> */
> void __serio_register_port(struct serio *serio, struct module *owner)
> {
> + if (!serio->write) {
> + pr_err("%s: refusing to register %s without write method\n",
> + __func__, serio->name);
> + return;
> + }
> serio_init_port(serio);
> serio_queue_event(serio, owner, SERIO_REGISTER_PORT);
> }
> diff --git a/include/linux/serio.h b/include/linux/serio.h
> index 6c27d413da92..075f1b8d76fa 100644
> --- a/include/linux/serio.h
> +++ b/include/linux/serio.h
> @@ -121,10 +121,7 @@ void serio_unregister_driver(struct serio_driver *drv);
>
> static inline int serio_write(struct serio *serio, unsigned char data)
> {
> - if (serio->write)
> - return serio->write(serio, data);
> - else
> - return -1;
> + return serio->write(serio, data);
> }
>
> static inline void serio_drv_write_wakeup(struct serio *serio)
> --
> 2.31.0.rc2.261.g7f71774620-goog
>
>
> --
> Dmitry
This patch as commit 81c7c0a350bf ("Input: serio - make write method
mandatory") in -next breaks input for my Hyper-V VM, which prevents me
from logging in. I attempted to do something like the following (-1 or
-EINVAL) which should be equivalent but it does not resolve the issue.
Cheers,
Nathan
diff --git a/drivers/input/serio/hyperv-keyboard.c b/drivers/input/serio/hyperv-keyboard.c
index 1a7b72a9016d..d3eee2d4c327 100644
--- a/drivers/input/serio/hyperv-keyboard.c
+++ b/drivers/input/serio/hyperv-keyboard.c
@@ -311,6 +311,11 @@ static void hv_kbd_stop(struct serio *serio)
spin_unlock_irqrestore(&kbd_dev->lock, flags);
}
+static int hv_kbd_write(struct serio *serio, u8 data)
+{
+ return -1;
+}
+
static int hv_kbd_probe(struct hv_device *hv_dev,
const struct hv_vmbus_device_id *dev_id)
{
@@ -341,6 +346,7 @@ static int hv_kbd_probe(struct hv_device *hv_dev,
hv_serio->start = hv_kbd_start;
hv_serio->stop = hv_kbd_stop;
+ hv_serio->write = hv_kbd_write;
error = vmbus_open(hv_dev->channel,
KBD_VSC_SEND_RING_BUFFER_SIZE,
