This prevents matching the wrong response packet, for example when
a mouse is moved while a packet is read. As a result, the reads are
more reliable and log spam is reduced.
Signed-off-by: Peter Wu <lekenst...@gmail.com>
---
src/linux/hidpp-device.c | 108 +++++++++++++++++++++++++++++++++--------------
1 file changed, 76 insertions(+), 32 deletions(-)
diff --git a/src/linux/hidpp-device.c b/src/linux/hidpp-device.c
index b53348f..6d02bf1 100644
--- a/src/linux/hidpp-device.c
+++ b/src/linux/hidpp-device.c
@@ -54,7 +54,7 @@
#define HIDPP_READ_LONG_REGISTER_DEVICE_TYPE_GAMEPAD 0xb
#define HIDPP_READ_LONG_REGISTER_DEVICE_TYPE_JOYSTICK 0xc
-#define HIDPP_ERR_INVALID_SUBID 0x8f
+#define HIDPP_ERROR_MESSAGE 0x8f
/* HID++ 2.0 */
@@ -146,6 +146,24 @@ G_DEFINE_TYPE (HidppDevice, hidpp_device, G_TYPE_OBJECT)
#define HIDPP_DEVICE_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o),
HIDPP_TYPE_DEVICE, HidppDevicePrivate))
/**
+ * hidpp_is_error:
+ *
+ * Checks whether a message is a protocol-level error.
+ */
+static gboolean
+hidpp_is_error(HidppMessage *msg, guchar *error)
+{
+ if (msg->type == HIDPP_MSG_TYPE_SHORT &&
+ msg->feature_idx == HIDPP_ERROR_MESSAGE) {
+ if (error)
+ *error = msg->s.params[1];
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+/**
* hidpp_device_map_print:
**/
static void
@@ -266,6 +284,7 @@ hidpp_device_cmd (HidppDevice *device,
gssize wrote;
HidppMessage read_msg = { 0 };
guint msg_len;
+ guchar error_code;
HidppDevicePrivate *priv = device->priv;
GPollFD poll[] = {
{
@@ -273,6 +292,8 @@ hidpp_device_cmd (HidppDevice *device,
.events = G_IO_IN | G_IO_OUT | G_IO_ERR,
},
};
+ guint64 begin_time;
+ gint remaining_time;
g_assert (request->type == HIDPP_MSG_TYPE_SHORT ||
request->type == HIDPP_MSG_TYPE_LONG);
@@ -292,41 +313,64 @@ hidpp_device_cmd (HidppDevice *device,
}
/* read from the device */
- // TODO: keep reading until wanted message is found
- wrote = g_poll (poll, G_N_ELEMENTS(poll),
- HIDPP_DEVICE_READ_RESPONSE_TIMEOUT);
- if (wrote <= 0) {
- g_set_error (error, 1, 0,
- "Attempt to read response from device timed out:
%" G_GSIZE_FORMAT,
- wrote);
- ret = FALSE;
- goto out;
- }
+ begin_time = g_get_monotonic_time () / 1000;
+ remaining_time = HIDPP_DEVICE_READ_RESPONSE_TIMEOUT;
+ for (;;) {
+ wrote = g_poll (poll, G_N_ELEMENTS(poll), remaining_time);
+ if (wrote <= 0) {
+ g_set_error (error, 1, 0,
+ "Attempt to read response from device
timed out: %" G_GSIZE_FORMAT,
+ wrote);
+ ret = FALSE;
+ goto out;
+ }
- wrote = read (priv->fd, &read_msg, sizeof (*response));
- if (wrote <= 0) {
- g_set_error (error, 1, 0,
- "Unable to read response from device: %"
G_GSIZE_FORMAT,
- wrote);
- ret = FALSE;
- goto out;
- }
+ wrote = read (priv->fd, &read_msg, sizeof (*response));
+ if (wrote <= 0) {
+ g_set_error (error, 1, 0,
+ "Unable to read response from device: %"
G_GSIZE_FORMAT,
+ wrote);
+ ret = FALSE;
+ goto out;
+ }
- hidpp_device_print_buffer (device, response);
+ hidpp_device_print_buffer (device, response);
- // TODO: test for invalid reply
-#if 0
- if ((buf[0] != HIDPP_HEADER_REQUEST && buf[0] != HIDPP_HEADER_RESPONSE)
||
- buf[1] != device_idx ||
- buf[2] != feature_idx ||
- buf[3] != function_idx) {
- g_set_error (error, 1, 0,
- "invalid response from device: %" G_GSIZE_FORMAT,
- wrote);
- ret = FALSE;
- goto out;
+ /* validate response */
+ if (read_msg.type != HIDPP_MSG_TYPE_SHORT &&
+ read_msg.type != HIDPP_MSG_TYPE_LONG) {
+ /* ignore key presses, mouse motions, etc. */
+ continue;
+ }
+
+ if (read_msg.feature_idx == request->feature_idx &&
+ read_msg.function_idx == request->function_idx) {
+ break;
+ }
+
+ /* recognize HID++ 1.0 errors */
+ if (hidpp_is_error(&read_msg, &error_code) &&
+ read_msg.function_idx == request->feature_idx &&
+ read_msg.s.params[0] == request->function_idx) {
+ g_set_error (error, 1, 0,
+ "Unable to satisfy request, HID++ error %02x",
error_code);
+ ret = FALSE;
+ goto out;
+ }
+
+ /* avoid infinite loop when there is no response */
+ remaining_time = HIDPP_DEVICE_READ_RESPONSE_TIMEOUT -
+ (g_get_monotonic_time () / 1000 - begin_time);
+ if (remaining_time <= 0) {
+ g_set_error (error, 1, 0,
+ "timeout while reading response");
+ ret = FALSE;
+ goto out;
+ }
+
+ /* not our message, ignore it and try again */
}
-#endif
+
out:
/* allow caller to check for protocol errors */
memcpy (response, &read_msg, sizeof (read_msg));
--
1.8.3.4
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