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From: Scott McNutt <smcnutt@psyent.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH v1 (WIP) 00/16] [Timer]API Rewrite
Date: Tue, 12 Jul 2011 11:23:20 -0400	[thread overview]
Message-ID: <4E1C66E8.6060300@psyent.com> (raw)
In-Reply-To: <20110712131042.74D0D16F7669@gemini.denx.de>

Dear Wolfgang

Wolfgang Denk wrote:

> What exactly is the reason that we cannot have better timer
> resolutions in NIOS?

You _can_ have better timer resolutions in Nios. However, there
are legacy systems that implement timer(s) with a fixed period
of 10 msec. The use of such implementations is very common.
How do I know? Because my customers have such implementations.
Why not upgrade? Because most sane engineers are loathe to
change their rtl just so they can fix a simple software bug
or add a simple custom feature.

My obvious preference is to continue to use the latest u-boot in
such systems ... without having to create a custom branch for
customers with older Nios implementations, where I use the old
timer interfaces ... simply because we "improved" the API.

> Scott, maybe you can comment here?

I have only one comment: Out of pure frustration, I have been
avoiding any discussions regarding this timer re-write effort.

> At the moment I'm trying to understand if we really have a problem on
> NIOS2 that cannot be fixed in a way that is compatible with our
> current plans.

This is where my frustration begins. I've said this several times
before, and I don't know how else to say this ... but I'll give it
one more try:

     This is not a Nios problem.

If I can't use a 10 msec timer interrupt to detect a simple timeout
condition when I'm programming a flash memory, then the timer API
design is garbage. And quite frankly, the enormous amount of
discussion in this matter reminds me of an undergraduate science
project.

> We also have to deal with decrementing counters, but this is just aan
> unimportant detail.  And it appears that we actually can have this,
> even on NIOS.

Wow! Even on Nios! Arrggghh!

> The only architecture I remember that seemed prolematic was NIOS

Really? There have been occasional issues that have required a patch
here and there. But I consider most of them far from "problematic."

This is exhausting. As I recall, this entire fuss was born out
of an issue with nested calls to get_timer() ... and that begat
removing reset_timer ... and that begat ... and so on. And we're
still spilling lots of intellectual seed here. And now we have
what? A jack-of-all-trades API that can do everything with
exacting precision ... other than handling a 10 msec interrupt?

Best Regards,
--Scott

  reply	other threads:[~2011-07-12 15:23 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-28 11:40 [U-Boot] [PATCH v1 (WIP) 00/16] [Timer]API Rewrite Graeme Russ
2011-06-28 11:40 ` [U-Boot] [PATCH v1 (WIP) 01/16] [Timer]Fix misuse of ARM *timer_masked() functions outside arch/arm Graeme Russ
2011-06-28 12:35   ` Andreas Bießmann
2011-07-11 21:57   ` Wolfgang Denk
2011-07-14 17:01     ` Albert ARIBAUD
2011-07-14 19:50       ` Wolfgang Denk
2011-07-14 23:24         ` Graeme Russ
2011-07-15  6:31           ` Wolfgang Denk
2011-07-15  7:00             ` Graeme Russ
2011-07-15 12:16   ` [U-Boot] [PATCH v2 1/7]Timer: Fix " Graeme Russ
2011-07-16  8:40     ` Albert ARIBAUD
2011-07-16  8:59       ` Graeme Russ
2011-07-16  9:12         ` Albert ARIBAUD
2011-07-16  9:31     ` [U-Boot] [PATCH v3 " Graeme Russ
2011-07-16  9:58       ` Albert ARIBAUD
2011-06-28 11:40 ` [U-Boot] [PATCH v1 (WIP) 02/16] [Timer]Remove calls to set_timer outside arch/ Graeme Russ
2011-07-11 21:58   ` Wolfgang Denk
2011-07-15 12:17   ` [U-Boot] [PATCH v2 2/7]Timer: Remove " Graeme Russ
2011-07-16  9:33     ` [U-Boot] [PATCH v3 " Graeme Russ
2011-07-26 12:52       ` Wolfgang Denk
2011-06-28 11:40 ` [U-Boot] [PATCH v1 (WIP) 03/16] [Timer]Remove calls to set_timer in arch/ Graeme Russ
2011-07-11 21:59   ` Wolfgang Denk
2011-07-15 12:18   ` [U-Boot] [PATCH v2 3/7]Timer: Remove set_timer completely Graeme Russ
2011-07-16  9:34     ` [U-Boot] [PATCH v3 " Graeme Russ
2011-07-26 12:52       ` Wolfgang Denk
2011-06-28 11:40 ` [U-Boot] [PATCH v1 (WIP) 04/16] [Timer]Allow reset_timer() only for Nios2 Graeme Russ
2011-07-11 22:01   ` Wolfgang Denk
2011-07-15 12:18   ` [U-Boot] [PATCH v2 4/7]Timer: Allow reset_timer() only for systems with low resolution timers Graeme Russ
2011-07-16  9:35     ` [U-Boot] [PATCH v3 " Graeme Russ
2011-07-26 12:53       ` Wolfgang Denk
2011-06-28 11:40 ` [U-Boot] [PATCH v1 (WIP) 05/16] [Timer]Remove reset_timer() for non-Nios2 arches Graeme Russ
2011-07-11 22:02   ` Wolfgang Denk
2011-07-15  0:01     ` Graeme Russ
2011-07-15 12:19   ` [U-Boot] [PATCH v2 5/7]Timer: Remove " Graeme Russ
2011-07-16  9:36     ` [U-Boot] [PATCH v3 " Graeme Russ
2011-07-26 12:53       ` Wolfgang Denk
2011-08-19 21:24         ` Mike Frysinger
2011-08-19 22:55           ` Graeme Russ
2011-08-19 23:12             ` Mike Frysinger
2011-09-28 19:24           ` Wolfgang Denk
2011-06-28 11:40 ` [U-Boot] [PATCH v1 (WIP) 06/16] [Timer]Fix at91rm9200/spi.c timer usage Graeme Russ
2011-06-28 12:30   ` Andreas Bießmann
2011-07-15 12:20   ` [U-Boot] [PATCH v2 6/7]Timer: Fix " Graeme Russ
2011-07-16  9:37     ` [U-Boot] [PATCH v3 " Graeme Russ
2011-07-26 12:54       ` Wolfgang Denk
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 07/16] [Timer]Remove reset_timer_masked() Graeme Russ
2011-07-11 22:04   ` Wolfgang Denk
2011-07-15 12:21   ` [U-Boot] [PATCH v2 7/7]Timer: Remove reset_timer_masked() Graeme Russ
2011-07-16  9:38     ` [U-Boot] [PATCH v3 " Graeme Russ
2011-07-26 12:54       ` Wolfgang Denk
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 08/16] [Timer]Create new userland timer API Graeme Russ
2011-06-29  4:31   ` Simon Glass
2011-06-29  4:36     ` Graeme Russ
2011-06-29  4:48       ` Simon Glass
2011-07-11 22:05   ` Wolfgang Denk
2011-07-11 22:32     ` Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 09/16] [Timer]Replace get_timer() usage in drivers/block/ Graeme Russ
2011-06-29  4:40   ` Simon Glass
2011-06-29  5:06     ` Reinhard Meyer
2011-06-29  5:19       ` Graeme Russ
2011-06-29  5:30         ` Simon Glass
2011-06-29  5:38           ` Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 10/16] [Timer]Replace get_timer() usage in driver/mtd and driver/block Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 11/16] [Timer]Remove reset_timer() completely Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 12/16] [Timer]Replace get_timer() usage in drivers/ Graeme Russ
2011-06-28 12:36   ` Vitaly Kuzmichev
2011-06-28 23:03     ` Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 13/16] [Timer]Replace get_timer() usage in net/ Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 14/16] [Timer]Replace get_timer() usage in common/ Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 15/16] [Timer]Replace get_timer() usage in board/ Graeme Russ
2011-06-28 11:41 ` [U-Boot] [PATCH v1 (WIP) 16/16] [Timer]Replace get_timer() usage in arch/ Graeme Russ
2011-06-29  4:45   ` Simon Glass
2011-06-29  4:51     ` Graeme Russ
2011-06-29  5:15       ` Mike Frysinger
2011-06-29  5:26         ` Mike Frysinger
2011-06-29  5:29           ` Graeme Russ
2011-06-29  4:54 ` [U-Boot] [PATCH v1 (WIP) 00/16] [Timer]API Rewrite Graeme Russ
2011-06-29  5:08 ` Mike Frysinger
2011-06-29  5:20   ` Graeme Russ
2011-07-08  0:25 ` Graeme Russ
2011-07-09  6:01   ` Albert ARIBAUD
2011-07-11 21:56 ` Wolfgang Denk
2011-07-11 22:49   ` Graeme Russ
2011-07-11 23:36   ` Graeme Russ
2011-07-12  2:17     ` Graeme Russ
2011-07-12  8:49       ` Wolfgang Denk
2011-07-12 10:36         ` Graeme Russ
2011-07-12 13:10           ` Wolfgang Denk
2011-07-12 15:23             ` Scott McNutt [this message]
2011-07-12 17:27               ` J. William Campbell
2011-07-13  0:29             ` Graeme Russ
2011-07-14 19:30               ` Wolfgang Denk
2011-07-17  1:51           ` Graeme Russ
2011-07-12 14:30       ` J. William Campbell
2011-07-12 16:08         ` Reinhard Meyer
2011-07-13  0:33           ` Graeme Russ
2011-07-13  1:20             ` J. William Campbell
2011-07-14 19:41               ` Wolfgang Denk
2011-07-14 23:52                 ` J. William Campbell
2011-07-15  7:17                   ` Wolfgang Denk
2011-07-15 18:08                     ` J. William Campbell
2011-07-15 18:34                       ` Wolfgang Denk
2011-07-15 21:03                         ` J. William Campbell
2011-07-16 14:11                           ` Graeme Russ
2011-07-15 12:15 ` [U-Boot] [PATCH v2 0/7]Timer: Simplify API Graeme Russ
2011-07-15 13:08   ` Graeme Russ
2011-07-16  8:36     ` Albert ARIBAUD
2011-07-16  9:01       ` Graeme Russ
2011-07-16  9:13         ` Albert ARIBAUD
2011-07-16  9:32         ` Wolfgang Denk

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