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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <Zwk3g-B6dJWgqE41@gofer.mess.org>
Date: Fri, 11 Oct 2024 15:34:43 +0100
From: Sean Young <sean@...s.org>
To: 金超-软件项目部 <jinchao@...o.com>
Cc: "mchehab@...nel.org" <mchehab@...nel.org>,
	黄理鹏 <huanglipeng@...o.com>,
	"linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: 回复: [PATCH v1] media: rc-core: Modify the timeout waiting time
 for the infrared remote control.

Hi,

On Wed, Oct 09, 2024 at 07:03:57AM +0000, 金超-软件项目部 wrote:
> NORMAL: The kukong apk control remote control sends codes for other buttons
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[0]: 4500, 4500, 560, 560, 560, 1680, 560, 1680
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[8]: 560, 1680, 560, 560, 560, 560, 560, 560
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[16]: 560, 560, 560, 560, 560, 1680, 560, 1680
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[24]: 560, 1680, 560, 560, 560, 560, 560, 560
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[32]: 560, 560, 560, 1680, 560, 560, 560, 1680
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[40]: 560, 1680, 560, 560, 560, 560, 560, 560
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[48]: 560, 560, 560, 560, 560, 1680, 560, 560
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[56]: 560, 560, 560, 1680, 560, 1680, 560, 1680
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: pattern[64]: 560, 1680, 560, 46920, 4500, 4500, 560, 1680
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: 0x560,
> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal: 0x96200,

If I sum all these lengths, I get 216000 microseconds. That's well clear
of IR_MAX_DURATION (500ms).

Note that the last two values 0x560 and 0x96200 look really weird, they are
not hex values are all, and there is no "pattern[...]: " prefix.

> 10-09 11:20:18.219  1023  1023 D ConsumerIrHal:
> 10-09 11:20:18.220  1023  1023 D ConsumerIrHal: IRTX: Send to driver
> 10-09 11:20:18.469  1023  1023 D ConsumerIrHal: Done, Turn OFF IRTX
> 
> SPECIAL :Sending the power button on the remote control of the kukong app may result in additional lines of coding, leading to transmission failure (72-88 extra)
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[0]: 4500, 4500, 560, 560, 560, 1680, 560, 1680
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[8]: 560, 1680, 560, 560, 560, 560, 560, 560
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[16]: 560, 560, 560, 560, 560, 1680, 560, 1680
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[24]: 560, 1680, 560, 560, 560, 560, 560, 560
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[32]: 560, 560, 560, 560, 560, 560, 560, 1680
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[40]: 560, 1680, 560, 560, 560, 560, 560, 560
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[48]: 560, 560, 560, 1680, 560, 1680, 560, 560
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[56]: 560, 560, 560, 1680, 560, 1680, 560, 1680
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[64]: 560, 1680, 560, 46920, 4500, 4500, 560, 1680
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[72]: 560, 96200, 4500, 4500, 560, 1680, 560, 96200
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[80]: 4500, 4500, 560, 1680, 560, 96200, 4500, 4500
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: pattern[88]: 560, 1680, 560, 96200, 4500, 4500, 560, 1680
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: 0x560,
> 10-09 11:19:53.973  1023  1023 D ConsumerIrHal: 0x96200,

If I sum all these lengths I get 648000 microseconds, so quit a bit more
than IR_MAX_DURATION, which is why the send fails. Again the last two values
are printed like garbage.

The signal looks like NECx1: http://hifi-remote.com/wiki/index.php/NECx1

So there is the main signal, follow by a bunch of repeats. Each repeat
looks like +4500 -4500 +560 -1680 +560 -96200; the -96200 is the trailing
gap. To avoid going over IR_MAX_DURATION, don't include the -96200 gap
but replaced with a usleep(96200), i.e. in psuedo code:

        int i, fd = open("/dev/lirc0", O_RDWR);
        write(fd, [4500 4500 560 560 560 1680 560 1680 560 1680 560 560 560 560 560 560 560 560 560 560 560 1680 560 1680 560 1680 560 560 560 560 560 560 560 560 560 560 560 560 560 1680 560 1680 560 560 560 560 560 560 560 560 560 1680 560 1680 560 560 560 560 560 1680 560 1680 560 1680 560 1680 560]);
        usleep(46920);
        for (i=0; i<4; i++) {
                write(fd, [4500 4500 560 1680 560]);
                usleep(96200);
        }

Note that this what the lirc daemon also does for transmits; it's a well
established way of sending. The write() to a lirc chardev won't return until
the transmit has been successful. It might be interruptted by a signal, so
you should disable signals during write (I don't think lirc daemon bothers
though).


Hope this helps

Sean