media: lirc: when transmitting scancodes, block until transmit is done (dde7edff) · Commits · 戴 / test

The semantics for lirc IR transmit with raw IR is that the write call should block until the IR is transmitted. Some drivers have no idea when this actually is (e.g. mceusb), so there is a wait. This is useful for userspace, as it might want to send a IR button press, a gap of a predefined number of milliseconds, and then send a repeat message. It turns out that for transmitting scancodes this feature is even more useful, as user space has no idea how long the IR is. So, maintain the existing semantics for IR scancode transmit. Signed-off-by:

Sean Young <sean@mess.org> Signed-off-by:

Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/rc/lirc-write.rst

+2 −2

Original line number	Diff line number	Diff line
		@@ -60,8 +60,8 @@ When in :ref:`LIRC_MODE_SCANCODE <lirc-mode-scancode>` mode, one
		and the protocol in the :c:type:`rc_proto`: member. All other members must be
		set to 0, else ``EINVAL`` is returned. If there is no protocol encoder
		for the protocol or the scancode is not valid for the specified protocol,
		``EINVAL`` is returned. The write function may not wait until the scancode
		is transmitted.
		``EINVAL`` is returned. The write function blocks until the scancode
		is transmitted by the hardware.


		Return Value

drivers/media/rc/lirc_dev.c

+11 −11

Original line number	Diff line number	Diff line
		@@ -354,6 +354,7 @@ static ssize_t ir_lirc_transmit_ir(struct file file, const char __user buf,
		duration += txbuf[i];

		ret *= sizeof(unsigned int);
		}

		/*
		* The lircd gap calculation expects the write function to
		@@ -366,7 +367,6 @@ static ssize_t ir_lirc_transmit_ir(struct file file, const char __user buf,
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(usecs_to_jiffies(towait));
		}
		}

		out:
		mutex_unlock(&dev->lock);

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