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media: ir_toy: prevent device from hanging during transmit

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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
[mchehab: renamed: s/STATE_RESET/STATE_COMMAND_NO_RESP/ ]
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Sean Young 2021-09-14 16:57:46 +02:00 committed by Mauro Carvalho Chehab
parent 2188488356
commit 4114978dcd
1 changed files with 20 additions and 1 deletions
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21
drivers/media/rc/ir_toy.c
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@ -26,6 +26,7 @@ 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'
@ -317,12 +318,30 @@ 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_COMMAND_NO_RESP);
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);