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| author | Bernhard Bender <bernhard.bender@bytecmed.com> | 2015-07-23 22:58:08 +0200 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2015-07-23 23:43:17 +0200 |
| commit | 968491709e5b1aaf429428814fff3d932fa90b60 (patch) | |
| tree | 370200624d8cbde19c03e053fa0dcac8370db16d /drivers/input | |
| parent | Input: elantech - force resolution of 31 u/mm (diff) | |
| download | linux-968491709e5b1aaf429428814fff3d932fa90b60.tar.xz linux-968491709e5b1aaf429428814fff3d932fa90b60.zip | |
Input: usbtouchscreen - avoid unresponsive TSC-30 touch screen
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.
Cc: stable@vger.kernel.org
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>
Diffstat (limited to 'drivers/input')
| -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 f2c6c352c55a..2c41107240de 100644 --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -627,6 +627,9 @@ 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), |