[PATCH] USB: PL2303 and TIOCMIWAIT

A while ago, I posted about TIOCMIWAIT not working with the PL2303
USB-serial adapter.

After a brief exchange with Greg, I tracked this to a missing wake-up
in the USB interrupt procedures. I got our systems staff to install
the enclosed very simple patch to our 2.6.12 kernels, and it all works
fine as expected. I guess this should also apply to the latest version
and go into the mainstream.

Apologies for the long delay in posting the result.

The routine being patched is pl2303_update_line_status

Signed-off-by: Julian Bradfield <jcb+luu@inf.ed.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index cf2213b..fb3b6b7 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -826,6 +826,7 @@ static void pl2303_update_line_status(struct usb_serial_port *port,
        spin_lock_irqsave(&priv->lock, flags);
        priv->line_status = data[status_idx];
        spin_unlock_irqrestore(&priv->lock, flags);
+       wake_up_interruptible (&priv->delta_msr_wait);
 
 exit:
        return;