Re: [PATCH v2 7/7] media: rc: mceusb: allow the timeout to be configurable

[Sean Young <sean@mess.org>]

Hello Hias,

On Tue, Apr 17, 2018 at 09:14:57PM +0200, Matthias Reichl wrote:
> On Sun, Apr 08, 2018 at 10:19:42PM +0100, Sean Young wrote:
> > mceusb devices have a default timeout of 100ms, but this can be changed.
> 
> We finally added a backport of the v2 series (and also the mce_kbd
> series) to LibreELEC yesterday and ratcher quickly received 2 bugreports
> from users using mceusb receivers.
> 
> Local testing on RPi/gpio-ir and Intel NUC/ite-cir was fine, I've
> been using the v2 series for over a week without issues on
> LibreELEC (RPi with kernel 4.14).
> 
> Here are the links to the bugreports and logs:
> https://forum.kodi.tv/showthread.php?tid=298461&pid=2726684#pid2726684
> https://forum.kodi.tv/showthread.php?tid=298462&pid=2726690#pid2726690
> 
> Both users are using similar mceusb receivers:
> 
> Log 1:
> [    6.418218] rc rc0: Media Center Ed. eHome Infrared Remote Transceiver (147a:e017) as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.0/rc/rc0
> [    6.418358] input: Media Center Ed. eHome Infrared Remote Transceiver (147a:e017) as /devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.0/rc/rc0/input0
> [    6.419443] rc rc0: lirc_dev: driver ir-lirc-codec (mceusb) registered at minor = 0
> [    6.608114] mceusb 1-1.3:1.0: Registered Formosa21 SnowflakeEmulation with mce emulator interface version 1
> [    6.608125] mceusb 1-1.3:1.0: 0 tx ports (0x0 cabled) and 1 rx sensors (0x1 active)
> 
> Log 2:
> [    3.023361] rc rc0: Media Center Ed. eHome Infrared Remote Transceiver (147a:e03e) as /devices/pci0000:00/0000:00:14.0/usb1/1-10/1-10:1.0/rc/rc0
> [    3.023393] input: Media Center Ed. eHome Infrared Remote Transceiver (147a:e03e) as /devices/pci0000:00/0000:00:14.0/usb1/1-10/1-10:1.0/rc/rc0/input11
> [    3.023868] rc rc0: lirc_dev: driver ir-lirc-codec (mceusb) registered at minor = 0
> [    3.119384] input: eventlircd as /devices/virtual/input/input21
> [    3.138625] ip6_tables: (C) 2000-2006 Netfilter Core Team
> [    3.196830] mceusb 1-10:1.0: Registered Formosa21 eHome Infrared Transceiver with mce emulator interface version 2
> [    3.196836] mceusb 1-10:1.0: 0 tx ports (0x0 cabled) and 1 rx sensors (0x1 active)
> 
> In both cases ir-keytable doesn't report any scancodes and the
> ir-ctl -r output contains very odd long space values where I'd expect
> a short timeout instead:
> 
> gap between messages:
> space 800
> pulse 450
> space 16777215
> space 25400
> pulse 2650
> space 800
> 
> end of last message:
> space 800
> pulse 450
> space 16777215
> timeout 31750
> 
> This patch applied cleanly on 4.14 and the mceusb history from
> 4.14 to media/master looked rather unsuspicious. I'm not 100% sure
> if I might have missed a dependency when backporting the patch
> or if this is indeed an issue of this patch on these particular
> (or maybe some more) mceusb receivers.

Thanks again for a great bug report and analysis! So, it seems with the
shorter timeout, some mceusb devices add a specific "timeout" code to
the IR data stream (0x80) rather than a space. The current mceusb code
resets the decoders in this case, causing the IR decoders to reset and
lirc to report a space of 0xffffff.

Turns out that one of my mceusb devices also suffers from this, I don't
know how I missed this. Anyway hopefully this will solve the problem.


Thanks

Sean

>From 92d27b206e51993e927dc0b3aba210a621eef3d0 Mon Sep 17 00:00:00 2001
From: Sean Young <sean@mess.org>
Date: Wed, 18 Apr 2018 10:36:25 +0100
Subject: [PATCH] media: rc: mceusb: IR of length 0 means IR timeout, not reset

The last usb packet with IR data will end with 0x80 (MCE_IRDATA_TRAILER).
If we reset the decoder state at this point, IR decoding can fail.

Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/media/rc/mceusb.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/media/rc/mceusb.c b/drivers/media/rc/mceusb.c
index c97cb2eb1c5f..5c0bf61fae26 100644
--- a/drivers/media/rc/mceusb.c
+++ b/drivers/media/rc/mceusb.c
@@ -1201,7 +1201,12 @@ static void mceusb_process_ir_data(struct mceusb_dev *ir, int buf_len)
 			if (ir->rem) {
 				ir->parser_state = PARSE_IRDATA;
 			} else {
-				ir_raw_event_reset(ir->rc);
+				init_ir_raw_event(&rawir);
+				rawir.timeout = 1;
+				rawir.duration = ir->rc->timeout;
+				if (ir_raw_event_store_with_filter(ir->rc,
+								   &rawir))
+					event = true;
 				ir->pulse_tunit = 0;
 				ir->pulse_count = 0;
 			}
-- 
2.14.3