On Thu, Nov 06, 2008 at 03:25:40PM +0000, Nuno Lucas wrote: > The usbtouchscreen module implements a driver for the TSC-10 DM USB > touchscreen controllers, but assumes a 2-byte response for the > CMD_RESET and CMD_RATE commands, when they can be only a single byte > when no EEPROM is connected. > > The driver worked with an earlier controller revision, but new > revisions of the controller fail. > > It seems the problem is that the early controller had the > SEL4/EEPROM-CS pin high, but the new controller has it down, making > the response different. > > Without the fix, the controller would answer the single byte 0x06 > (ACK), making the init fail with -ENODEV because buf[1] is 0xFF (as > initialized before). > > As the single byte is the only thing we need to check it was ok, there > is no need to verify the second byte. > > The [0x15 0x01] case is the NAK [0x15] response for when there is no > data in the EEPROM [bit-0 of second byte set], so I let that be, as I > don't have any controller with an EEPROM. > > With this patch, both the earlier and latest controller work the same. > > Note: This was previously submited as BUG #11961 [1] on the bugzilla > tracker, but rebased to version 2.6.27.4 and with unnecessary comments > and printk's removed. > > > Signed-off-by: Nuno Lucas <ntlucas@xxxxxxxxx> > > > [1] http://bugzilla.kernel.org/show_bug.cgi?id=11961 > diff -urNp linux-2.6.27.4/drivers/input/touchscreen/usbtouchscreen.c linux-2.6.27.4-patched/drivers/input/touchscreen/usbtouchscreen.c > --- linux-2.6.27.4/drivers/input/touchscreen/usbtouchscreen.c 2008-10-25 23:05:07.000000000 +0100 > +++ linux-2.6.27.4-patched/drivers/input/touchscreen/usbtouchscreen.c 2008-11-06 15:07:49.000000000 +0000 > @@ -424,7 +424,7 @@ static int dmc_tsc10_init(struct usbtouc > 0, 0, buf, 2, USB_CTRL_SET_TIMEOUT); > if (ret < 0) > goto err_out; > - if (buf[0] != 0x06 || buf[1] != 0x00) { > + if (buf[0] != 0x06) { > ret = -ENODEV; > goto err_out; > } > @@ -437,8 +437,7 @@ static int dmc_tsc10_init(struct usbtouc > TSC10_RATE_150, 0, buf, 2, USB_CTRL_SET_TIMEOUT); > if (ret < 0) > goto err_out; > - if ((buf[0] != 0x06 || buf[1] != 0x00) && > - (buf[0] != 0x15 || buf[1] != 0x01)) { > + if ((buf[0] != 0x06) && (buf[0] != 0x15 || buf[1] != 0x01)) { > ret = -ENODEV; > goto err_out; > } Daniel, have you seen this? -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
