diff options
| author | Bernhard Bender <bernhard.bender@bytecmed.com> | 2015-07-23 13:58:08 -0700 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-08-19 08:36:39 +0200 |
| commit | 251414e371dfdfcee1fcfaf387ad8c3a8f14f927 (patch) | |
| tree | f14e8f078d9bf9ff54563c8ff70e77775ce93d85 | |
| parent | d1cb2e267b31e60b9f4629434ed60b99e1ed50f2 (diff) | |
| download | lwn-251414e371dfdfcee1fcfaf387ad8c3a8f14f927.tar.gz lwn-251414e371dfdfcee1fcfaf387ad8c3a8f14f927.zip | |
Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen
commit 968491709e5b1aaf429428814fff3d932fa90b60 upstream.
This patch fixes a problem in the usbtouchscreen driver for DMC TSC-30
touch screen. Due to a missing delay between the RESET and SET_RATE
commands, the touch screen may become unresponsive during system startup or
driver loading.
According to the DMC documentation, a delay is needed after the RESET
command to allow the chip to complete its internal initialization. As this
delay is not guaranteed, we had a system where the touch screen
occasionally did not send any touch data. There was no other indication of
the problem.
The patch fixes the problem by adding a 150ms delay between the RESET and
SET_RATE commands.
Suggested-by: Jakob Mustafa <jakob.mustafa@bytecmed.com>
Signed-off-by: Bernhard Bender <bernhard.bender@bytecmed.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | drivers/input/touchscreen/usbtouchscreen.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c index e565530e3596..5679cd9003cc 100644 --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -628,6 +628,9 @@ static int dmc_tsc10_init(struct usbtouch_usb *usbtouch) goto err_out; } + /* TSC-25 data sheet specifies a delay after the RESET command */ + msleep(150); + /* set coordinate output rate */ buf[0] = buf[1] = 0xFF; ret = usb_control_msg(dev, usb_rcvctrlpipe (dev, 0), |