From: "Marek Behún" <kabel@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-serial@vger.kernel.org, "Pali Rohár" <pali@kernel.org>
Subject: Re: [PATCH 5/7] USB: serial: ftdi_sio: Fix baudrate rounding for ASYNC_SPD_CUST
Date: Thu, 7 Jul 2022 18:08:18 +0200 [thread overview]
Message-ID: <20220707180818.53b7e79a@dellmb> (raw)
In-Reply-To: <Ysb3hNJ6wPRe+oxo@kroah.com>
On Thu, 7 Jul 2022 17:11:00 +0200
Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> On Thu, Jul 07, 2022 at 04:53:52PM +0200, Marek Behún wrote:
> > From: Pali Rohár <pali@kernel.org>
> >
> > Use DIV_ROUND_CLOSEST() for more accurate baudrate calculation for
> > ASYNC_SPD_CUST instead of rounding it just down.
>
> Why? What does this change or fix?
To compute more accurate baudrate when given custom divisor.
User requests a baudrate B.
Application uses old API, so it computes divisor D for baudrate B.
The driver then tries to compute back the requested baudrate B. To
compute it back more accurately, rounding to closes value should be
used.
Marek
next prev parent reply other threads:[~2022-07-07 16:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-07 14:53 [PATCH 0/7] ftdi_sio driver improvements Marek Behún
2022-07-07 14:53 ` [PATCH 1/7] USB: serial: ftdi_sio: Fix divisor overflow Marek Behún
2022-07-07 15:07 ` Greg Kroah-Hartman
2022-07-07 15:37 ` Marek Behún
2022-07-07 15:50 ` Greg Kroah-Hartman
2022-07-07 14:53 ` [PATCH 2/7] USB: serial: ftdi_sio: Add missing baudrate validation Marek Behún
2022-07-07 15:08 ` Greg Kroah-Hartman
2022-07-07 16:22 ` Marek Behún
2022-07-07 16:50 ` Greg Kroah-Hartman
2022-07-07 14:53 ` [PATCH 3/7] USB: serial: ftdi_sio: Extract SIO divisor code to function Marek Behún
2022-07-07 15:06 ` Greg Kroah-Hartman
2022-07-07 15:41 ` Marek Behún
2022-07-07 15:09 ` Greg Kroah-Hartman
2022-07-07 15:50 ` Marek Behún
2022-07-07 14:53 ` [PATCH 4/7] USB: serial: ftdi_sio: Do not reset baudrate to 9600 on error Marek Behún
2022-07-07 15:10 ` Greg Kroah-Hartman
2022-07-07 15:52 ` Marek Behún
2022-07-07 16:06 ` Greg Kroah-Hartman
2022-07-08 15:51 ` Andy Shevchenko
2022-07-12 11:28 ` m.brock
2022-07-12 12:09 ` Marek Behún
2022-07-12 12:11 ` Marek Behún
2022-07-07 14:53 ` [PATCH 5/7] USB: serial: ftdi_sio: Fix baudrate rounding for ASYNC_SPD_CUST Marek Behún
2022-07-07 15:11 ` Greg Kroah-Hartman
2022-07-07 16:08 ` Marek Behún [this message]
2022-07-07 16:12 ` Greg Kroah-Hartman
2022-07-07 14:53 ` [PATCH 6/7] USB: serial: ftdi_sio: Fix custom_divisor and c_*speed " Marek Behún
2022-07-07 14:53 ` [PATCH 7/7] USB: serial: ftdi_sio: Fill c_*speed fields with real baudrate Marek Behún
2022-07-07 15:11 ` Greg Kroah-Hartman
2022-07-07 15:07 ` [PATCH 0/7] ftdi_sio driver improvements Greg Kroah-Hartman
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