Hi,
Oliver Neukum 於 2015/11/4 下午 04:38 寫道:
On Wed, 2015-11-04 at 16:19 +0800, Peter Hung wrote:
Hi
Oliver Neukum 於 2015/11/3 下午 06:03 寫道:
On Tue, 2015-11-03 at 11:51 +0800, Peter Hung wrote:
+ for (i = 0; i < F81534_NUM_PORT; ++i)
+ atomic_set(&serial_priv->port_active[i], 0);
Should be ATOMIC_INIT()
ATOMIC_INIT() seems to be used only for variable initializer, It cant be
used for dynamic allocation. Should I change it to a normal boolean
flag protecting with spin_lock ?
No, if it doesn't work, use the current code.
OK, I'll use current code.
+static void f81534_compare_msr(struct usb_serial_port *port, u8 *msr,
Is the point of passing a pointer to msr locking?
+ bool is_port_open)
This function is used only with URB callback function. The *msr is
reported by H/W with newest MSR. The USB-Serial generic system will
re-submit read URB when callback complete. So this function should
run once on the same time.
Yes, so why don't you pass an u8 as opposed to a pointer to an u8?
I'll re-write it from u8* to u8.
+static int f81534_tiocmget(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
+ unsigned long flags;
+ int r;
+ u8 msr, mcr;
+
+ /*
+ * We'll avoid to direct read MSR register. The IC will read the MSR
+ * changed and report it f81534_process_per_serial_block() by
+ * F81534_TOKEN_MSR_CHANGE.
+ *
+ * When this device in heavy loading (e.g., BurnInTest Loopback Test)
+ * The report of MSR register will delay received a bit. It's due to
+ * MSR interrupt is lowest priority in 16550A. So we decide to sleep
+ * a little time to pass the test.
+ */
+ if (schedule_timeout_interruptible(
+ msecs_to_jiffies(F81534_DELAY_READ_MSR))) {
+ dev_info(&port->dev, "%s: breaked !!\n", __func__);
+ }
Is the delay necessary or isn't it?
If it is necessary you should do something about the signal.
We add this delay due to stress test (Loop-back & 921600bps with
BurnInTest). It'll receive MSR with some delay when connecting with
DTR-DSR & RTS/CTS, but the delay smaller than 10ms. So we decided to
delay some time to pass the test.
OK, but how do you guarantee the delay you need if you get a signal,
which would abort the delay?
Hmm, you are right. It seems to replace *_interruptible to
*_killable and return -EINTR to guarantee not abort by normal
signal.
Thanks for your advices
--
With Best Regards,
Peter Hung
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