From: Pavan Savoy <pavan_savoy@sify.com>
To: linux-serial@vger.kernel.org
Cc: pavan_savoy@sify.com
Subject: serial_core's port->count mess
Date: Thu, 19 May 2011 15:08:52 +0530 [thread overview]
Message-ID: <BANLkTim=dgCwFTeCyz273nBq4MGQs1FJsw@mail.gmail.com> (raw)
Hi,
I have a device connected to my apps processor over UART, the serial
core's hooked up with omap-serial UART driver.
There is a scenario, where the device just fails to respond, and I
should be closing the UART & opening it again to re-try the request.
This is also coupled with power-cycling the chip.
However a normal start/stop sequence where chip responds to every
request & I close UART when I'm done - is something like this,
[function name & line number in logs)
uart_open(1) called
uart_open: 1635
uart_open: 1651
uart_open: 1663
uart_open: 1674
omap-hsuart omap-hsuart.1: serial_omap_pm+1
omap-hsuart omap-hsuart.1: Enable CTS wakeup for UART 1
omap-hsuart omap-hsuart.1: serial_omap_startup+1
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
omap-hsuart omap-hsuart.1: serial_omap_get_mctrl+1
uart_open: 1686
uart_open: 1694
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
omap-hsuart omap-hsuart.1: serial_omap_set_termios+1
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
uart_open: 1705
uart_flush_buffer(1) called
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
omap-hsuart omap-hsuart.1: serial_omap_set_termios+1
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
omap-hsuart omap-hsuart.1: serial_omap_set_termios+1
uart_flush_buffer(1) called
uart_flush_buffer(1) called
uart_flush_buffer(1) called
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
omap-hsuart omap-hsuart.1: serial_omap_set_termios+1
uart_wait_until_sent(1), jiffies=4294954470, expire=4294954474...
omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1
uart_wait_until_sent(1), jiffies=4294954471, expire=4294954475...
omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1
(stc): st_tty_open
uart_flush_buffer(1) called
uart_flush_buffer(1) called
uart_flush_buffer(1) called
(stk) :ldisc_install = 0
uart_close(1) called
uart_close: 1295
uart_close: 1316
uart_wait_until_sent(1), jiffies=4294951992, expire=4294951996...
omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1
uart_close: 1327
omap-hsuart omap-hsuart.1: Disable CTS wakeup for UART1
uart_wait_until_sent(1), jiffies=4294951994, expire=4294951996...
omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1
uart_close: 1345
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
omap-hsuart omap-hsuart.1: serial_omap_shutdown+1
omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1
uart_flush_buffer(1) called
uart_flush_buffer(1) called
omap-hsuart omap-hsuart.1: serial_omap_pm+1
uart_close: 1368
(stc): st_tty_close
However, in a scenario where the chip fails to respond to one of the
requests, the start/stop sequence becomes something like this,
uart_open(1) called
uart_open: 1635
uart_open: 1651
uart_open: 1663
uart_open: 1705
So, the problem seems to be that the port->count in the serial_core
isn't 1 & hence the call,
if (port->count == 1)
uart_change_pm(state, 0);
doesn't seem to be happening, which is very critical. Also no calls
are made to uart_startup & hence omap-serial's startup.
Where should I be looking as to why the port->count is messed up ?
What is the this count used for?
Also how is this related to chip not responding to certain commands?
next reply other threads:[~2011-05-19 9:38 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-19 9:38 Pavan Savoy [this message]
2011-05-19 10:25 ` serial_core's port->count mess Alan Cox
[not found] ` <BANLkTim7OmA1y+Z_4CHZBCKu-uG_=9jJ=A@mail.gmail.com>
2011-05-19 12:51 ` Pavan Savoy
[not found] ` <BANLkTik6f4rFcr+X=ov4y=48QCxF1=zvkg@mail.gmail.com>
2011-05-19 13:17 ` Pavan Savoy
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='BANLkTim=dgCwFTeCyz273nBq4MGQs1FJsw@mail.gmail.com' \
--to=pavan_savoy@sify.com \
--cc=linux-serial@vger.kernel.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).