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authorBenjamin Tissoires <benjamin.tissoires@redhat.com>2014-04-25 02:26:38 +0400
committerJiri Kosina <jkosina@suse.cz>2014-05-13 18:42:50 +0400
commitdcce583792d2b9a83dd9cb62551831f09f971fda (patch)
treeb699e7bed4a729a10bf0fa5cb110bbd44483a167 /drivers/hid/hid-rmi.c
parentf15475c397f496c0907be5e95f8556c8f5908d54 (diff)
downloadlinux-dcce583792d2b9a83dd9cb62551831f09f971fda.tar.xz
HID: rmi: do not fetch more than 16 bytes in a query
A firmware bug is present on the XPS Haswell edition which silently split the request in two responses when the caller ask for a read of more than 16 bytes. The FW sends the first 16 then the 4 next, but it says that it answered the 20 bytes in the first report. This occurs only on the retrieving of the min/max of X and Y of the F11 function. We only use the first 10 bytes of the Ctrl register, so we can get only those 10 bytes to prevent the bug from happening. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1090161 Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid/hid-rmi.c')
-rw-r--r--drivers/hid/hid-rmi.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index eda7ef41c291..05e4928c06f1 100644
--- a/drivers/hid/hid-rmi.c
+++ b/drivers/hid/hid-rmi.c
@@ -641,10 +641,15 @@ static int rmi_populate_f11(struct hid_device *hdev)
}
}
- /* retrieve the ctrl registers */
- ret = rmi_read_block(hdev, data->f11.control_base_addr, buf, 20);
+ /*
+ * retrieve the ctrl registers
+ * the ctrl register has a size of 20 but a fw bug split it into 16 + 4,
+ * and there is no way to know if the first 20 bytes are here or not.
+ * We use only the first 10 bytes, so get only them.
+ */
+ ret = rmi_read_block(hdev, data->f11.control_base_addr, buf, 10);
if (ret) {
- hid_err(hdev, "can not read ctrl block of size 20: %d.\n", ret);
+ hid_err(hdev, "can not read ctrl block of size 10: %d.\n", ret);
return ret;
}