From: "Chris Doré" <cdore@connecttech.com>
To: linux-serial@vger.kernel.org
Cc: 'Paul Gortmaker' <paul.gortmaker@windriver.com>
Subject: RE: Output character lost with 8250 UART driver
Date: Wed, 25 Jun 2008 10:00:15 -0400 [thread overview]
Message-ID: <005a01c8d6cb$ccd363d0$667a2b70$@com> (raw)
In-Reply-To: <1214381202.6938.76.camel@xzhang1-desktop>
> -----Original Message-----
> From: ZhangXiao
> Sent: June 25, 2008 4:07 AM
>
> Based on theses lines, characters should be written to the THR
> continuous, no matter if it had already move the character to the TSR. I
> think it is not safe in some cases so I add a line
>
> wait_for_xmitr(up, UART_LSR_THRE);
>
> before line 3. And then the issue in my target was disappeared. This is
> a static function that was already exist in the same file. It just check
> and wait until the THR was empty.
Do you have the FIFO's disabled, but transmit_chars() thinks they are
enabled?
Sounds to me like that might be your problem and without the
wait_for_xmitr() call you are overrunning the transmitter. In other words,
if you have FIFOs disabled, up->tx_loadsz should be 1.
What UART are you using?
..Chris
prev parent reply other threads:[~2008-06-25 14:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-25 8:06 Output character lost with 8250 UART driver ZhangXiao
2008-06-25 14:00 ` Chris Doré [this message]
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='005a01c8d6cb$ccd363d0$667a2b70$@com' \
--to=cdore@connecttech.com \
--cc=linux-serial@vger.kernel.org \
--cc=paul.gortmaker@windriver.com \
/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