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| author | Ellen Wang <ellen@cumulusnetworks.com> | 2015-07-08 11:17:39 -0700 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.com> | 2015-07-09 14:15:53 +0200 |
| commit | 5ddfb12e90c73cf86881345be422e09c367f6981 (patch) | |
| tree | a8e76a63d4a61f07f34d4f8a1d98a638c340634a /drivers/hid/hid-cp2112.c | |
| parent | 6debce6f4e787a8eb4cec94e7afa85fb4f40db27 (diff) | |
| download | linux-stable-5ddfb12e90c73cf86881345be422e09c367f6981.tar.gz linux-stable-5ddfb12e90c73cf86881345be422e09c367f6981.tar.bz2 linux-stable-5ddfb12e90c73cf86881345be422e09c367f6981.zip | |
HID: cp2112: support large i2c transfers
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 <ellen@cumulusnetworks.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
Diffstat (limited to 'drivers/hid/hid-cp2112.c')
| -rw-r--r-- | drivers/hid/hid-cp2112.c | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c index a2dbbbe0d8d7..75398cb84fde 100644 --- a/drivers/hid/hid-cp2112.c +++ b/drivers/hid/hid-cp2112.c @@ -511,13 +511,30 @@ 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; + if (ret == 0) { + hid_err(hdev, "read returned 0\n"); + ret = -EIO; + 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: |