Commit f0c15b36 authored by Sean Young's avatar Sean Young Committed by Mauro Carvalho Chehab
Browse files

media: ir_toy: prevent device from hanging during transmit 

If the IR Toy is receiving IR while a transmit is done, it may end up
hanging. We can prevent this from happening by re-entering sample mode
just before issuing the transmit command.

Link: https://github.com/bengtmartensson/HarcHardware/discussions/25



Cc: stable@vger.kernel.org
Signed-off-by: default avatarSean Young <sean@mess.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 3ad02c27

drivers/media/rc/ir_toy.c

+20 −1
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ static const u8 COMMAND_VERSION[] = { 'v' }; 
// End transmit and repeat reset command so we exit sump mode

static const u8 COMMAND_RESET[] = { 0xff, 0xff, 0, 0, 0, 0, 0 };

static const u8 COMMAND_SMODE_ENTER[] = { 's' };

static const u8 COMMAND_SMODE_EXIT[] = { 0 };

static const u8 COMMAND_TXSTART[] = { 0x26, 0x24, 0x25, 0x03 };



#define REPLY_XMITCOUNT 't'
@@ -309,12 +310,30 @@ static int irtoy_tx(struct rc_dev *rc, uint *txbuf, uint count) 
		buf[i] = cpu_to_be16(v);

	}



	buf[count] = cpu_to_be16(0xffff);

	buf[count] = 0xffff;



	irtoy->tx_buf = buf;

	irtoy->tx_len = size;

	irtoy->emitted = 0;



	// There is an issue where if the unit is receiving IR while the

	// first TXSTART command is sent, the device might end up hanging

	// with its led on. It does not respond to any command when this

	// happens. To work around this, re-enter sample mode.

	err = irtoy_command(irtoy, COMMAND_SMODE_EXIT,

			    sizeof(COMMAND_SMODE_EXIT), STATE_RESET);

	if (err) {

		dev_err(irtoy->dev, "exit sample mode: %d\n", err);

		return err;

	}



	err = irtoy_command(irtoy, COMMAND_SMODE_ENTER,

			    sizeof(COMMAND_SMODE_ENTER), STATE_COMMAND);

	if (err) {

		dev_err(irtoy->dev, "enter sample mode: %d\n", err);

		return err;

	}



	err = irtoy_command(irtoy, COMMAND_TXSTART, sizeof(COMMAND_TXSTART),

			    STATE_TX);

	kfree(buf);