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From: Johan Hovold <johan@kernel.org>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Balakrishna Godavarthi <bgodavar@codeaurora.org>,
	Johan Hovold <johan@kernel.org>,
	marcel@holtmann.org, johan.hedberg@gmail.com,
	linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org,
	hemantg@codeaurora.org, linux-arm-msm@vger.kernel.org,
	Johan Hovold <jhovold@gmail.com>
Subject: Re: [PATCH v5 2/5] Bluetooth: hci_qca: Deassert RTS while baudrate change command
Date: Thu, 17 Jan 2019 17:09:44 +0100	[thread overview]
Message-ID: <20190117160944.GV3691@localhost> (raw)
In-Reply-To: <20190115234628.GQ261387@google.com>

On Tue, Jan 15, 2019 at 03:46:28PM -0800, Matthias Kaehlcke wrote:

> Using RTS seems|ed like a nice solutions, since it's the native way to
> prevent the controller from sending data, instead of doing some custom
> hack. However Johan seems to be fairly convinced that flow control and
> manual toggling of RTS can be problematic, and we have seen that
> disabling flow control has its own problems. Maybe it's time to
> consider other solutions like the DISCARD_RX flag we discussed
> earlier. Not that I really liked this custom solution, but in the end
> it might be a more robust way to address the issue.
> 
> Johan/Marcel/others: Do you have any further ideas or input on this?

I don't see why deasserting RTS wouldn't work, well at least as long as
the RTS signal is wired correctly.

My point was simply that calling serdev_device_set_rts() will generally
not work unless you first disable automatic (i.e. hw-managed) flow
control using serdev_device_set_flow_control(). The exact behaviour is
serial-controller dependent, but I assume the driver needs to be
platform agnostic.

Johan

  reply	other threads:[~2019-01-17 16:09 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-20 14:46 [PATCH v5 0/5] Bug fixes for Qualcomm BT chip wcn3990 Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 1/5] Bluetooth: hci_qca: use wait_until_sent() for power pulses Balakrishna Godavarthi
2018-12-22  1:59   ` Matthias Kaehlcke
2018-12-26  6:31     ` Balakrishna Godavarthi
2018-12-26 22:21       ` Matthias Kaehlcke
2018-12-27  3:23         ` Balakrishna Godavarthi
2019-01-09 14:38     ` Johan Hovold
2019-01-10 14:48       ` Balakrishna Godavarthi
2019-01-11  0:55         ` Matthias Kaehlcke
2019-01-11 14:32           ` Balakrishna Godavarthi
2019-01-11 23:38             ` Matthias Kaehlcke
2019-01-14 10:25               ` Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 2/5] Bluetooth: hci_qca: Deassert RTS while baudrate change command Balakrishna Godavarthi
2018-12-22  0:31   ` Matthias Kaehlcke
2018-12-26  5:45     ` Balakrishna Godavarthi
2018-12-26 20:25       ` Matthias Kaehlcke
2018-12-27  3:20         ` Balakrishna Godavarthi
2019-01-09 14:52   ` Johan Hovold
2019-01-10 14:34     ` Balakrishna Godavarthi
2019-01-10 14:39       ` Johan Hovold
2019-01-10 14:52         ` Balakrishna Godavarthi
2019-01-11  1:37           ` Matthias Kaehlcke
2019-01-11 15:07             ` Balakrishna Godavarthi
2019-01-11 23:56               ` Matthias Kaehlcke
2019-01-14 14:52                 ` Balakrishna Godavarthi
2019-01-15 23:46                   ` Matthias Kaehlcke
2019-01-17 16:09                     ` Johan Hovold [this message]
2019-01-17 17:21                       ` Matthias Kaehlcke
2019-01-18  9:44                         ` Johan Hovold
2019-01-19  0:31                           ` Matthias Kaehlcke
2019-01-21  8:56                             ` Johan Hovold
2019-01-22 21:39                               ` Matthias Kaehlcke
2019-01-21 14:41                             ` Balakrishna Godavarthi
2019-01-22 21:53                               ` Matthias Kaehlcke
2019-01-23 12:57                                 ` Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 3/5] Bluetooth: hci_qca: Fix frame reassembly errors for wcn3990 Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 4/5] Bluetooth: hci_qca: Disable IBS state machine and flush Tx buffer Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 5/5] Bluetooth: btqca: inject command complete event during fw download Balakrishna Godavarthi

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