From: "David Härdeman" <david@hardeman.nu>
To: pboettcher@kernellabs.com
Cc: linux-media@vger.kernel.org
Subject: dib0700 NEC scancode question
Date: Thu, 27 Mar 2014 13:07:28 +0100 [thread overview]
Message-ID: <20140327120728.GA13748@hardeman.nu> (raw)
Hi Patrick,
a quick question regarding the dib0700 driver:
in ./media/usb/dvb-usb/dib0700_core.c the RC RX packet is defined as:
struct dib0700_rc_response {
u8 report_id;
u8 data_state;
union {
u16 system16;
struct {
u8 not_system;
u8 system;
};
};
u8 data;
u8 not_data;
};
The NEC protocol transmits in the order:
system
not_system
data
not_data
Does the dib0700 fw really reorder the bytes, or could the order of
not_system and system in struct dib0700_rc_response have been
accidentally reversed?
Note that the NEC extended keycode is later defined in dib0700_core.c as:
keycode = be16_to_cpu(poll_reply->system16) << 8 | poll_reply->data;
i.e.
keycode = poll_reply->not_system << 16 |
poll_reply->system << 8 |
poll_reply->data;
Which, if the order *is* reversed, would mean that the scancode that
gets defined is in reality:
keycode = poll_reply->system << 16 |
poll_reply->not_system << 8 |
poll_reply->data;
Which is the same as the order used in drivers/media/rc/ir-nec-decoder.c.
(An order which I'm considering trying to correct, which is why I'm
checking all the places where NEC scancodes are generated).
--
David Härdeman
next reply other threads:[~2014-03-27 12:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-27 12:07 David Härdeman [this message]
2014-03-27 21:40 ` dib0700 NEC scancode question David Härdeman
2014-03-27 22:13 ` Patrick Boettcher
2014-03-27 23:43 ` David Härdeman
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