linux-bluetooth.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Matthias Kaehlcke <mka@chromium.org>
To: Johan Hovold <johan@kernel.org>
Cc: Balakrishna Godavarthi <bgodavar@codeaurora.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 09:21:09 -0800	[thread overview]
Message-ID: <20190117172109.GU261387@google.com> (raw)
In-Reply-To: <20190117160944.GV3691@localhost>

On Thu, Jan 17, 2019 at 05:09:44PM +0100, Johan Hovold wrote:
> 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.

I observed that the qcom_geni_serial driver doesn't raise RTS with
flow control disabled. It seems we have to investigate why that's the
case. I agree that the driver should be platform agnostic.

Cheers

Matthias

  reply	other threads:[~2019-01-17 17:21 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
2019-01-17 17:21                       ` Matthias Kaehlcke [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190117172109.GU261387@google.com \
    --to=mka@chromium.org \
    --cc=bgodavar@codeaurora.org \
    --cc=hemantg@codeaurora.org \
    --cc=jhovold@gmail.com \
    --cc=johan.hedberg@gmail.com \
    --cc=johan@kernel.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-bluetooth@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=marcel@holtmann.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).