linux-kernel - Re: [PATCH v4 00/21] OMAP UART Patches

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Date:	Wed, 12 Sep 2012 09:23:01 +0300
From:	Felipe Balbi <balbi@...com>
To:	Paul Walmsley <paul@...an.com>
Cc:	Felipe Balbi <balbi@...com>, Greg KH <gregkh@...uxfoundation.org>,
	alan@...ux.intel.com, Tony Lindgren <tony@...mide.com>,
	Kevin Hilman <khilman@...com>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Linux ARM Kernel Mailing List 
	<linux-arm-kernel@...ts.infradead.org>,
	linux-serial@...r.kernel.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Shubhrajyoti Datta <shubhrajyoti@...com>,
	Sourav Poddar <sourav.poddar@...com>
Subject: Re: [PATCH v4 00/21] OMAP UART Patches

Hi,

On Tue, Sep 11, 2012 at 10:02:48PM +0000, Paul Walmsley wrote:
> 
> Hi Felipe
> 
> Just tested these OMAP serial changes at commit 
> e36851d0fa94b0f7802b3cc80406dbd3ef4f2f16 ("serial: omap: fix compile 
> breakage").  There's good news and bad news...
> 
> The good news is that after applying this series, the 'OMAP4 UART garbage 
> on long transmit buffers when PM is enabled' bug:
> 
> http://www.pwsan.com/omap/testlogs/test_v3.6-rc5/20120908202511/pm/4430es2panda/4430es2panda_log.txt
> 
> ... goes away.  (Unclear if it's because the underlying bug was fixed, or 
> if unrelated changes are masking it.)  Not sure what caused the problem to 
> go away exactly, but it's one of the changes between d37c6ceb and bf63a08.  
> So that's good!

I'd point the finger at sticking to put_autosuspend() as that would give
HW enough time to actually unload all bytes from its FIFO through the
UART lines. can you check if forcing the autosuspend_delay to -1
triggers the issue again ? If it does, it's some help from autosuspend,
which would mean we still have the problem and needs to be properly
fixed.

> The bad news is that N800 no longer boots -- or the UART dies during 
> serial init:
> 
> http://www.pwsan.com/omap/testlogs/test_tty_next_e36851d0/20120910020323/boot/2420n800/2420n800_log.txt
> 
> The problem doesn't seem to affect the 2430SDP.
> 
> Could you put together a patch to fix N800?

I'll see what I can do. BTW, is that log with DEBUG_LL enabled ?

cheers

-- 
balbi

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