lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Tue, 14 Apr 2015 10:15:13 -0700
From:	Randy Dunlap <rdunlap@...radead.org>
To:	Dmitry Khromov <dk@...logic.net>, linux-kernel@...r.kernel.org
CC:	gregkh@...uxfoundation.org, Evgeniy Polyakov <zbr@...emap.net>
Subject: Re: [PATCH] Introduce an ability to specify microseconds bus scanning
 intervals in w1 core

On 04/14/15 00:40, Dmitry Khromov wrote:
> DS1990* "iButtons" and compatible RFID card readers commonly found at
> physical access control systems are usually attached/generate presence
> for as short as 100 ms - hence the tens-to-hundreds milliseconds scan
> intervals are required.
> 
> Tested on Raspberry Pi model B+ with DS2482-100 bus master,
> tens-of-milliseconds intervals are easily achieved without significant
> CPU load (and with unknown accuracy), and though I doubt
> microseconds-scale intervals are really feasible in terms of practical
> use and underlying buses timings, I believe it makes sense to give the
> ability of using them to those willing to try.
> 
> Signed-off-by: Dmitry Khromov <dk@...logic.net>
> Acked-by: Evgeniy Polyakov <zbr@...emap.net>
> 
>  drivers/w1/w1.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> ---
> diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
> index 181f41c..73b4e2d 100644
> --- a/drivers/w1/w1.c
> +++ b/drivers/w1/w1.c
> @@ -46,11 +46,15 @@ MODULE_AUTHOR("Evgeniy Polyakov <zbr@...emap.net>");
>  MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
>  
>  static int w1_timeout = 10;
> +static int w1_timeout_us = 0;
>  int w1_max_slave_count = 64;
>  int w1_max_slave_ttl = 10;
>  
>  module_param_named(timeout, w1_timeout, int, 0);
>  MODULE_PARM_DESC(timeout, "time in seconds between automatic slave searches");
> +module_param_named(timeout_us, w1_timeout_us, int, 0);
> +MODULE_PARM_DESC(timeout, "time in microseconds between automatic slave"
> +                         "searches");

The description string needs a space between "slave" and "searches".

>  /* A search stops when w1_max_slave_count devices have been found in that
>   * search.  The next search will start over and detect the same set of devices
>   * on a static 1-wire bus.  Memory is not allocated based on this number, just


-- 
~Randy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists