Input: cleanup ps2_command() timeout handling in libps2. (905ab9d1) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/input/serio/libps2.c

+62 −28

Original line number	Diff line number	Diff line
		@@ -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);
		}