From: Andi Shyti <andi.shyti@samsung.com>
To: Sean Young <sean@mess.org>
Cc: "Mauro Carvalho Chehab" <mchehab@osg.samsung.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
linux-media@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, "Andi Shyti" <andi@etezian.org>,
"David Härdeman" <david@hardeman.nu>
Subject: Re: [PATCH v2 5/7] [media] ir-lirc-codec: don't wait any transmitting time for tx only devices
Date: Thu, 27 Oct 2016 16:44:01 +0900 [thread overview]
Message-ID: <20161027074401.wxg5icc6hcpwnfsf@gangnam.samsung> (raw)
In-Reply-To: <20160902084158.GA25342@gofer.mess.org>
Hi Sean,
it's been a while :)
I was going through your review fixing what needs to be fixed,
but...
> > @@ -153,7 +153,7 @@ static ssize_t ir_lirc_transmit_ir(struct file *file, const char __user *buf,
> > }
> >
> > ret = dev->tx_ir(dev, txbuf, count);
> > - if (ret < 0)
> > + if (ret < 0 || dev->driver_type == RC_DRIVER_IR_RAW_TX)
>
> Just because a driver only does transmit doesn't mean its transmit ABI
> should change.
>
> Now this bit of code is pretty horrible. It ensures that the call to write()
> takes at least as long as the length of the transmit IR by sleeping. That's
> not much of a guarantee that the IR has been sent.
>
> Note that in the case of ir-spi, since your spi transfer is sync no sleep
> should be introduced here.
>
> The gap calculation in lirc checks that if the call to write() took _longer_
> than expected wait before sending the next IR code (when either multiple
> IR codes or repeats are specified). Introducing the sleep in the kernel
> here does not help at all, lirc already ensures that it waits as long as
> the IR is long (see schedule_repeat_timer in lirc).
>
> This change was introduced in 3.10, commit f8e00d5.
... I'm not sure what can be done here. I get your point and I
understand that this indeed is a kind of fake sync point and by
doing this I
How about creating two different functions:
- ir_lirc_transmit_ir where we actually do what the function
already does
- ir_lirc_transmit_no_sync where the function we don't wait
because the the sync is done on a different level (for example
in the SPI case).
SPI does approximately the same thing.
Andi
next prev parent reply other threads:[~2016-10-27 13:57 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-01 17:16 [PATCH v2 0/7] Add support for IR transmitters Andi Shyti
2016-09-01 17:16 ` [PATCH v2 1/7] [media] rc-main: assign driver type during allocation Andi Shyti
2016-09-01 21:23 ` Sean Young
2016-09-02 5:25 ` Andi Shyti
2016-09-01 17:16 ` [PATCH v2 2/7] [media] rc-main: split setup and unregister functions Andi Shyti
2016-09-01 17:16 ` [PATCH v2 3/7] [media] rc-core: add support for IR raw transmitters Andi Shyti
2016-09-01 21:31 ` Sean Young
2016-09-02 0:21 ` kbuild test robot
2016-09-01 17:16 ` [PATCH v2 4/7] [media] rc-ir-raw: do not generate any receiving thread for " Andi Shyti
2016-09-01 17:16 ` [PATCH v2 5/7] [media] ir-lirc-codec: don't wait any transmitting time for tx only devices Andi Shyti
2016-09-02 8:41 ` Sean Young
2016-10-27 7:44 ` Andi Shyti [this message]
2016-10-27 14:36 ` Sean Young
2016-10-31 14:31 ` David Härdeman
2016-10-31 17:05 ` Sean Young
2016-11-01 6:51 ` Andi Shyti
2016-11-01 10:34 ` Sean Young
2016-11-02 4:39 ` Andi Shyti
2016-09-01 17:16 ` [PATCH v2 6/7] Documentation: bindings: add documentation for ir-spi device driver Andi Shyti
2016-09-01 21:40 ` Rob Herring
2016-09-02 5:33 ` Andi Shyti
2016-09-12 13:27 ` Rob Herring
2016-09-01 17:16 ` [PATCH v2 7/7] [media] rc: add support for IR LEDs driven through SPI Andi Shyti
2016-09-01 21:12 ` Sean Young
2016-09-02 5:27 ` Andi Shyti
2016-09-02 8:43 ` Sean Young
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