cp2112_i2c_xfer() only reads up to 61 bytes, returning EIO on longers reads. The fix is to wrap a loop around cp2112_read() to pick up all the returned data.
Signed-off-by: Ellen Wang <[email protected]> --- This is like the previous patch but with the controversial part left out. --- drivers/hid/hid-cp2112.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c index 3318de6..5a72819 100644 --- a/drivers/hid/hid-cp2112.c +++ b/drivers/hid/hid-cp2112.c @@ -509,13 +509,25 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, if (!(msgs->flags & I2C_M_RD)) goto finish; - ret = cp2112_read(dev, msgs->buf, msgs->len); - if (ret < 0) - goto power_normal; - if (ret != msgs->len) { - hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len); - ret = -EIO; - goto power_normal; + for (count = 0; count < msgs->len;) { + ret = cp2112_read(dev, msgs->buf + count, msgs->len - count); + if (ret < 0) + goto power_normal; + count += ret; + if (count > msgs->len) { + /* + * The hardware returned too much data. + * This is mostly harmless because cp2112_read() + * has a limit check so didn't overrun our + * buffer. Nevertheless, we return an error + * because something is seriously wrong and + * it shouldn't go unnoticed. + */ + hid_err(hdev, "long read: %d > %zd\n", + ret, msgs->len - count + ret); + ret = -EIO; + goto power_normal; + } } finish: -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
