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

From: Felipe Balbi
Date: Wed Sep 12 2012 - 02:27:40 EST


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:
> ... 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

> The bad news is that N800 no longer boots -- or the UART dies during
> serial init:
> 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 ?



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