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From: Tony Lindgren <tony@atomide.com>
To: Sanjeev Premi <premi@ti.com>
Cc: Thomas Weber <weber@corscience.de>,
	Gregoire Gentil <gregoire@gentil.com>,
	Hrishikesh Bhandiwad <hrishikesh.b@ti.com>,
	Jason Lam <lzg@ema-tech.com>,
	linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv2] omap3: beagle: Use GPTIMER1 for clockevents
Date: Mon, 27 Jun 2011 04:15:57 -0700	[thread overview]
Message-ID: <20110627111556.GM23145@atomide.com> (raw)
In-Reply-To: <1309171009-8075-1-git-send-email-premi@ti.com>

* Sanjeev Premi <premi@ti.com> [110627 03:33]:
> From: Hrishikesh Bhandiwad <hrishikesh.b@ti.com>
> 
> Present current selection of the GPTIMER on Beagleboard
> was result of a hardware issue in early versions of the
> Beagleboards (Ax and B1 thru B4). [1][2]
> 
> Its been long since the hardware issue has been fixed.
> This patch uses GPTIMER 1 for all newer board revisions
> incl. Beagleboard XM.
> 
> Also, the clock source for GPTIMER12 is much less frequency
> stable than clock sources for GPTIMER1. Using GPTIMER12 can
> result in major time skew over a fairly short interval.

I don't think omap3_beagle_init_rev is even called when
the timer is set?

But even if it was, this is not a good fix because of the
dependency issues it causes to mux and gpio framework in
omap3_beagle_rev_init.

The best way to fix this is to set a separate machine ID
for the working beagle boards like I commented earlier.
It allows just setting the .timer based on that, the rest
of the code can be shared.

Regards,

Tony

WARNING: multiple messages have this Message-ID (diff)
From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv2] omap3: beagle: Use GPTIMER1 for clockevents
Date: Mon, 27 Jun 2011 04:15:57 -0700	[thread overview]
Message-ID: <20110627111556.GM23145@atomide.com> (raw)
In-Reply-To: <1309171009-8075-1-git-send-email-premi@ti.com>

* Sanjeev Premi <premi@ti.com> [110627 03:33]:
> From: Hrishikesh Bhandiwad <hrishikesh.b@ti.com>
> 
> Present current selection of the GPTIMER on Beagleboard
> was result of a hardware issue in early versions of the
> Beagleboards (Ax and B1 thru B4). [1][2]
> 
> Its been long since the hardware issue has been fixed.
> This patch uses GPTIMER 1 for all newer board revisions
> incl. Beagleboard XM.
> 
> Also, the clock source for GPTIMER12 is much less frequency
> stable than clock sources for GPTIMER1. Using GPTIMER12 can
> result in major time skew over a fairly short interval.

I don't think omap3_beagle_init_rev is even called when
the timer is set?

But even if it was, this is not a good fix because of the
dependency issues it causes to mux and gpio framework in
omap3_beagle_rev_init.

The best way to fix this is to set a separate machine ID
for the working beagle boards like I commented earlier.
It allows just setting the .timer based on that, the rest
of the code can be shared.

Regards,

Tony

  reply	other threads:[~2011-06-27 11:15 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-27 10:36 [PATCHv2] omap3: beagle: Use GPTIMER1 for clockevents Sanjeev Premi
2011-06-27 10:36 ` Sanjeev Premi
2011-06-27 11:15 ` Tony Lindgren [this message]
2011-06-27 11:15   ` Tony Lindgren
2011-06-27 12:12   ` Premi, Sanjeev
2011-06-27 12:12     ` Premi, Sanjeev
2011-06-27 12:31     ` Tony Lindgren
2011-06-27 12:31       ` Tony Lindgren
2011-06-27 13:28       ` Premi, Sanjeev
2011-06-27 13:28         ` Premi, Sanjeev
2011-06-27 18:00         ` Tony Lindgren
2011-06-27 18:00           ` Tony Lindgren
2011-06-27 19:04         ` Kevin Hilman
2011-06-27 19:04           ` Kevin Hilman

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