From: Balakrishna Godavarthi <bgodavar@codeaurora.org>
To: Johan Hovold <johan@kernel.org>
Cc: Matthias Kaehlcke <mka@chromium.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
Subject: Re: [PATCH v8 1/3] Bluetooth: hci_qca: use wait_until_sent() for power pulses
Date: Thu, 17 Jan 2019 22:25:33 +0530 [thread overview]
Message-ID: <21ac40f7314788e2d25b97628f998eb3@codeaurora.org> (raw)
In-Reply-To: <20190117161331.GW3691@localhost>
On 2019-01-17 21:43, Johan Hovold wrote:
> On Thu, Jan 17, 2019 at 03:55:17PM +0530, Balakrishna Godavarthi wrote:
>> Hi Matthias,
>>
>> On 2019-01-17 01:52, Matthias Kaehlcke wrote:
>
>> >> - /* Wait for 100 uS for SoC to settle down */
>> >> - usleep_range(100, 200);
>> >> + serdev_device_wait_until_sent(hu->serdev, timeout);
>> >> + /* Wait of 5ms is required for assuring to send the byte on the Tx
>> >> + * line and also for the controller to settle down for the received
>> >> + * byte.
>> >> + */
>> >> + usleep_range(5000, 6000);
>> >
>> > I incorrectly claimed that there might be still bytes sitting in the
>> > UART FIFO when serdev_device_wait_until_sent() returns, Johan
>> > corrected me on that (thanks!). So if it takes the SoC 100us to settle
>> > down we should be good with the original code.
>>
>> [Bala]: sure will revert, i think he commented that wait_until_sent()
>> will only guarantee circular buffer is empty. if wait_until_sent()
>> guarantee us that the data was transmitted from the FIFO, then 100us
>> will work.
>
> No, Matthias is correct; I claimed that the UART FIFO will be empty (at
> least as long as flow control is disabled, otherwise it may never empty
> and we therefore also have a time out).
>
> Johan
[Bala]: Thanks Johan for clarification.
--
Regards
Balakrishna.
next prev parent reply other threads:[~2019-01-17 16:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 11:46 [PATCH v8 0/3] Bug fixes for Qualcomm BT chip wcn3990 Balakrishna Godavarthi
2019-01-16 11:46 ` [PATCH v8 1/3] Bluetooth: hci_qca: use wait_until_sent() for power pulses Balakrishna Godavarthi
2019-01-16 20:22 ` Matthias Kaehlcke
2019-01-17 10:25 ` Balakrishna Godavarthi
2019-01-17 16:13 ` Johan Hovold
2019-01-17 16:55 ` Balakrishna Godavarthi [this message]
2019-01-24 11:20 ` Balakrishna Godavarthi
2019-01-16 11:46 ` [PATCH v8 2/3] Bluetooth: hci_qca: Deassert RTS while baudrate change command Balakrishna Godavarthi
2019-01-16 11:46 ` [PATCH v8 3/3] Bluetooth: hci_qca: Disable IBS state machine and flush Tx buffer Balakrishna Godavarthi
2019-01-16 23:08 ` Matthias Kaehlcke
2019-01-17 10:27 ` 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=21ac40f7314788e2d25b97628f998eb3@codeaurora.org \
--to=bgodavar@codeaurora.org \
--cc=hemantg@codeaurora.org \
--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 \
--cc=mka@chromium.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).