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ltunify: fix do_read failure when receiving unrelated messages

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When a touchpad event occurs while the device is being queried (e.g.
for features), then do_io (for do_read) would fail because the report
was not of the correct type (0x20 vs 0x11 for example). To fix this,
make do_read retry reads (within the allowed timeout).

Previously the expected report type was hidden in the msg parameter,
make this expected report type more explicit now in a new parameter.
This commit is contained in:
Peter Wu
2013-09-28 16:19:14 +02:00
parent bcdc930b76
commit 8fbf5f92d2
2 changed files with 60 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
Makefile
View File

@@ -17,6 +17,7 @@ all: ltunify read-dev-usbmon
read-dev-usbmon: read-dev-usbmon.c hidraw.c
ltunify: ltunify.c hidpp20.c
$(CC) $(CFLAGS) -o $(OUTDIR)$@ $< -lrt
.PHONY: all clean install-home install install-udevrule uninstall
clean:

88
ltunify.c
View File

@@ -31,6 +31,7 @@
#include <getopt.h> /* for getopt_long */
#include <poll.h>
#include <libgen.h> /* for basename, used during discovery */
#include <time.h> /* needs -lrt, for clock_gettime as timeout helper */
#ifndef PACKAGE_VERSION
# define PACKAGE_VERSION "0.2"
@@ -40,6 +41,7 @@
// pass -D option to print very verbose details like protocol communication
static bool debug_enabled;
#define DPRINTF(...) if (debug_enabled) { fprintf(stderr, __VA_ARGS__); }
typedef unsigned char u8;
@@ -306,18 +308,25 @@ static void dump_msg(struct hidpp_message *msg, size_t payload_size, const char
fflush(NULL);
}
static ssize_t do_io(int fd, struct hidpp_message *msg, bool is_write, int timeout) {
ssize_t r;
size_t payload_size = SHORT_MESSAGE_LEN;
static long long unsigned get_timestamp_ms(void) {
struct timespec tp;
clock_gettime(CLOCK_MONOTONIC, &tp);
return tp.tv_sec * 1000 + tp.tv_nsec / 1000000;
}
if (msg->report_id == LONG_MESSAGE) {
payload_size = LONG_MESSAGE_LEN;
}
#include <execinfo.h>
static ssize_t do_read(int fd, struct hidpp_message *msg, u8 expected_report_id, int timeout) {
ssize_t r;
size_t payload_size = LONG_MESSAGE_LEN;
long long unsigned begin_ms, end_ms;
if (is_write) {
dump_msg(msg, payload_size, "wr");
r = write(fd, msg, payload_size);
} else {
if (expected_report_id == SHORT_MESSAGE) {
payload_size = SHORT_MESSAGE_LEN;
}
begin_ms = get_timestamp_ms();
while (timeout > 0) {
struct pollfd pollfd;
pollfd.fd = fd;
pollfd.events = POLLIN;
@@ -327,32 +336,55 @@ static ssize_t do_io(int fd, struct hidpp_message *msg, bool is_write, int timeo
perror("poll");
return 0;
} else if (r == 0) {
DPRINTF("poll timeout reached!\n");
// timeout
return 0;
}
memset(msg, 0, payload_size);
r = read(fd, msg, payload_size);
if (r >= 0) {
int saved_errno = errno;
if (r < 0) {
perror("read");
return 0;
} else if (r > 0) {
dump_msg(msg, r, "rd");
errno = saved_errno;
if (msg->report_id == expected_report_id) {
return r;
} else if (expected_report_id == 0 &&
(msg->report_id == SHORT_MESSAGE ||
msg->report_id == LONG_MESSAGE)) {
/* HACK: ping response for HID++ 2.0 is a LONG
* message, but for HID++ 1.0 it is a SHORT one. */
return r;
} else {
DPRINTF("Skipping unexpected report ID %#x (want %#x)\n",
msg->report_id, expected_report_id);
}
}
}
if ((size_t) r == payload_size
|| (msg->report_id == SUB_ERROR_MSG && r == SHORT_MESSAGE_LEN)) {
return payload_size;
/* unexpected message, try again with updated timeout */
end_ms = get_timestamp_ms();
timeout -= end_ms - begin_ms;
begin_ms = end_ms;
}
if (r < 0) {
perror(is_write ? "write" : "read");
}
/* timeout expired, no report found unfortunately */
return 0;
}
static ssize_t do_read(int fd, struct hidpp_message *msg, int timeout) {
return do_io(fd, msg, false, timeout);
}
static ssize_t do_write(int fd, struct hidpp_message *msg) {
return do_io(fd, msg, true, 0);
ssize_t r, payload_size = SHORT_MESSAGE_LEN;
if (msg->report_id == LONG_MESSAGE) {
payload_size = LONG_MESSAGE_LEN;
}
dump_msg(msg, payload_size, "wr");
r = write(fd, msg, payload_size);
if (r < 0) {
perror("write");
}
return payload_size == r ? payload_size : 0;
}
const char *get_report_id_str(u8 report_type) {
@@ -407,8 +439,7 @@ bool process_notif_dev_connect(struct hidpp_message *msg, u8 *device_index,
static bool do_read_skippy(int fd, struct hidpp_message *msg,
u8 exp_report_id, u8 exp_sub_id) {
for (;;) {
msg->report_id = exp_report_id;
if (!do_read(fd, msg, 2000)) {
if (!do_read(fd, msg, exp_report_id, 2000)) {
return false;
}
if (msg->report_id == exp_report_id && msg->sub_id == exp_sub_id) {
@@ -653,8 +684,7 @@ void perform_pair(int fd, u8 timeout) {
puts("Please turn your wireless device off and on to start pairing.");
// WARNING: mess ahead. I knew it would become messy before writing it.
for (;;) {
msg.report_id = SHORT_MESSAGE;
if (!do_read(fd, &msg, timeout * 1000 + 2000)) {
if (!do_read(fd, &msg, SHORT_MESSAGE, timeout * 1000 + 2000)) {
fprintf(stderr, "Failed to read short message\n");
break;
}
@@ -824,7 +854,7 @@ bool get_hidpp_version(int fd, u8 device_index, struct hidpp_version *version) {
return false;
}
for (;;) {
if (!do_read(fd, &msg, 3000)) {
if (!do_read(fd, &msg, 0, 3000)) {
if (debug_enabled) {
fprintf(stderr, "Failed to read HID++ version, device does not respond!\n");
}