linux-kernel - [PATCH v1] media: rc-core: Modify the timeout waiting time for the infrared remote control.

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Message-Id: <20240927105808.9284-1-shenlichuan@vivo.com>
Date: Fri, 27 Sep 2024 18:58:08 +0800
From: Shen Lichuan <shenlichuan@...o.com>
To: sean@...s.org,
	mchehab@...nel.org
Cc: huanglipeng@...o.com,
	linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	opensource.kernel@...o.com,
	Shen Lichuan <shenlichuan@...o.com>
Subject: [PATCH v1] media: rc-core: Modify the timeout waiting time for the infrared remote control.

When transmitting codes from certain infrared remote controls, the kernel
occasionally fails to receive them due to a timeout during transmission.

This issue arises specifically in instances where the duration of the 
signal exceeds the predefined limit (`IR_MAX_DURATION`) in the code
handling logic located within `lirc_dev.c`:

if (txbuf[i] > IR_MAX_DURATION - duration || !txbuf[i]) {
	pr_err("lirc_transmit duration out range[%d] txbuf:%d duration:%d\n",
		i, txbuf[i], duration);
	ret = -EINVAL;
	goto out_kfree;
}

The error manifests as an `EINVAL` (error number 22) being returned when
attempting to send infrared signals whose individual elements exceed the
maximum allowed duration (`xbuf[i] > IR_MAX_DURATION - duration`).

As evidenced by logs, attempts to send commands with extended durations,
such as those associated with the "Power" button on a Skyworth TV remote,
fail with this error.

To rectify this and ensure compatibility with a broader range of infrared
remote controls, particularly those with lengthy code sequences, this patch
proposes to increase the value of `IR_MAX_DURATION`. 

This adjustment will allow for successful transmission of these extended
codes, thereby enhancing overall device compatibility and ensuring proper
functionality of remotes with long duration signals.

Example log entries highlighting the issue:
	D ConsumerIrHal: IRTX: Send to driver <268>
	E ConsumerIrHal: irtx write fail, errno=22 <269>
	D ConsumerIrHal: Done, Turn OFF IRTX <270>

Modifying the maximum timeout time in this area can solve this issue.

Signed-off-by: Huang Lipeng <huanglipeng@...o.com>
Signed-off-by: Shen Lichuan <shenlichuan@...o.com>
---
 include/media/rc-core.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/media/rc-core.h b/include/media/rc-core.h
index d095908073ef..2f575c18b6b6 100644
--- a/include/media/rc-core.h
+++ b/include/media/rc-core.h
@@ -303,7 +303,7 @@ struct ir_raw_event {

 #define US_TO_NS(usec)		((usec) * 1000)
 #define MS_TO_US(msec)		((msec) * 1000)
-#define IR_MAX_DURATION		MS_TO_US(500)
+#define IR_MAX_DURATION		MS_TO_US(1000)
 #define IR_DEFAULT_TIMEOUT	MS_TO_US(125)
 #define IR_MAX_TIMEOUT		LIRC_VALUE_MASK

-- 
2.17.1