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From: mad_soft@inbox.ru (Dmitry Artamonow)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH/RFC 2/2] arm/tegra: add timeout to PCIe PLL lock detection loop
Date: Wed, 7 Mar 2012 00:15:38 +0400	[thread overview]
Message-ID: <20120306201538.GA14350@rainbow> (raw)
In-Reply-To: <4F56424A.3020305@wwwdotorg.org>

On 09:58 Tue 06 Mar     , Stephen Warren wrote:
> On 03/06/2012 01:45 AM, Dmitry Artamonow wrote:
> > Tegra PCIe driver waits for PLL to lock using busy loop.
> > If PLL fails to lock for some reason, this leads to silent lockup
> > while booting (as PCIe code is not modular).
> > 
> > Fix by adding timeout, so if PLL doesn't lock in a couple
> > of seconds, just PCIe driver fails and machine continues to boot.
> > 
> > Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
> 
> That seems reasonable. So once the mdelay discussion is resolved,
> 
> Acked-by: Stephen Warren <swarren@wwwdotorg.org>
> 
> Any idea why the PLL doesn't lock sometimes?


Please dismiss this patch - I forgot to turn 'return' to 'return 0' at
the end of the function, while converting it's type from void to int,
and it causes driver to fail always now. I'll send updated version shortly.

Also I've managed to get another Harmony board today, and it doesn't have
problems with PLL locking (PLL locks on it in about 2ms), so probably the
issue I've seen is caused by some hardware fault on the first board,
or is specific to some particular revision of the board and/or Tegra2 chip.

I'll do more testing tomorrow and re-spin the patches.
-- 
Best regards,
Dmitry "MAD" Artamonow

  parent reply	other threads:[~2012-03-06 20:15 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-06  8:45 [PATCH/RFC 0/2] Couple of Tegra2 PCIe fixes(?) Dmitry Artamonow
2012-03-06  8:45 ` [PATCH/RFC 1/2] arm/tegra: fix harmony pinmux for PCIe Dmitry Artamonow
2012-03-06 16:55   ` Stephen Warren
2012-03-06  8:45 ` [PATCH/RFC 2/2] arm/tegra: add timeout to PCIe PLL lock detection loop Dmitry Artamonow
2012-03-06  9:38   ` Andi
2012-03-06 11:19     ` Dmitry Artamonow
2012-03-06 16:58   ` Stephen Warren
2012-03-06 19:09     ` Thierry Reding
2012-03-06 20:15     ` Dmitry Artamonow [this message]
2012-03-09 10:09       ` [PATCH v2 " Dmitry Artamonow
2012-03-12 18:09         ` Stephen Warren
2012-03-12 19:30           ` Dmitry Artamonow
2012-03-12 19:56             ` Olof Johansson
2012-03-13  5:46               ` [PATCH] arm/tegra: pcie: fix return value of function Dmitry Artamonow
2012-03-13 19:36                 ` Stephen Warren
2012-03-18 17:27                   ` Olof Johansson
2012-03-07  6:38   ` [PATCH/RFC 2/2] arm/tegra: add timeout to PCIe PLL lock detection loop Thierry Reding

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