Input: cleanup ps2_command() timeout handling in libps2.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
index 92b92ee0379177d291e01c829f94a11e6f34cdf8..d4c990f7c85e9a1f64c2f03340ad01e625eaf29c 100644 (file)
--- a/drivers/input/serio/libps2.c
+++ b/drivers/input/serio/libps2.c
@@ -97,6 +97,66 @@ void ps2_drain(struct ps2dev *ps2dev, int maxbytes, int timeout)
        up(&ps2dev->cmd_sem);
 }
 
+/*
+ * ps2_is_keyboard_id() checks received ID byte against the list of
+ * known keyboard IDs.
+ */
+
+static inline int ps2_is_keyboard_id(char id_byte)
+{
+       static char keyboard_ids[] = {
+               0xab,   /* Regular keyboards            */
+               0xac,   /* NCD Sun keyboard             */
+               0x2b,   /* Trust keyboard, translated   */
+               0x5d,   /* Trust keyboard               */
+               0x60,   /* NMB SGI keyboard, translated */
+               0x47,   /* NMB SGI keyboard             */
+       };
+
+       return memchr(keyboard_ids, id_byte, sizeof(keyboard_ids)) != NULL;
+}
+
+/*
+ * ps2_adjust_timeout() is called after receiving 1st byte of command
+ * response and tries to reduce remaining timeout to speed up command
+ * completion.
+ */
+
+static int ps2_adjust_timeout(struct ps2dev *ps2dev, int command, int timeout)
+{
+       switch (command) {
+               case PS2_CMD_RESET_BAT:
+                       /*
+                        * Device has sent the first response byte after
+                        * reset command, reset is thus done, so we can
+                        * shorten the timeout.
+                        * The next byte will come soon (keyboard) or not
+                        * at all (mouse).
+                        */
+                       if (timeout > msecs_to_jiffies(100))
+                               timeout = msecs_to_jiffies(100);
+                       break;
+
+               case PS2_CMD_GETID:
+                       /*
+                        * If device behind the port is not a keyboard there
+                        * won't be 2nd byte of ID response.
+                        */
+                       if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
+                               serio_pause_rx(ps2dev->serio);
+                               ps2dev->flags = ps2dev->cmdcnt = 0;
+                               serio_continue_rx(ps2dev->serio);
+                               timeout = 0;
+                       }
+                       break;
+
+               default:
+                       break;
+       }
+
+       return timeout;
+}
+
 /*
  * ps2_command() sends a command and its parameters to the mouse,
  * then waits for the response and puts it in the param array.
@@ -150,33 +210,7 @@ int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 
        if (ps2dev->cmdcnt && timeout > 0) {
 
-               if (command == PS2_CMD_RESET_BAT && timeout > msecs_to_jiffies(100)) {
-                       /*
-                        * Device has sent the first response byte
-                        * after a reset command, reset is thus done,
-                        * shorten the timeout. The next byte will come
-                        * soon (keyboard) or not at all (mouse).
-                        */
-                       timeout = msecs_to_jiffies(100);
-               }
-
-               if (command == PS2_CMD_GETID &&
-                   ps2dev->cmdbuf[receive - 1] != 0xab && /* Regular keyboards */
-                   ps2dev->cmdbuf[receive - 1] != 0xac && /* NCD Sun keyboard */
-                   ps2dev->cmdbuf[receive - 1] != 0x2b && /* Trust keyboard, translated */
-                   ps2dev->cmdbuf[receive - 1] != 0x5d && /* Trust keyboard */
-                   ps2dev->cmdbuf[receive - 1] != 0x60 && /* NMB SGI keyboard, translated */
-                   ps2dev->cmdbuf[receive - 1] != 0x47) { /* NMB SGI keyboard */
-                       /*
-                        * Device behind the port is not a keyboard
-                        * so we don't need to wait for the 2nd byte
-                        * of ID response.
-                        */
-                       serio_pause_rx(ps2dev->serio);
-                       ps2dev->flags = ps2dev->cmdcnt = 0;
-                       serio_continue_rx(ps2dev->serio);
-               }
-
+               timeout = ps2_adjust_timeout(ps2dev, command, timeout);
                wait_event_timeout(ps2dev->wait,
                                   !(ps2dev->flags & PS2_FLAG_CMD), timeout);
        }
@@ -190,7 +224,7 @@ int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
 
        rc = 0;
 
-out:
+ out:
        serio_pause_rx(ps2dev->serio);
        ps2dev->flags = 0;
        serio_continue_rx(ps2dev->serio);