Re: [REGRESSION] commit 0461a41 "spi: Pump transfers inside calling context for spi_sync()" breaks Apalis/Colibri T30 with MCP2515 SPI CAN controller

From: Marc Kleine-Budde
Date: Fri Apr 10 2015 - 11:16:23 EST


On 04/10/2015 03:23 PM, Mark Brown wrote:
> On Fri, Apr 10, 2015 at 03:00:53PM +0200, Marcel Ziswiler wrote:
>> Hi there
>
> Please try to use somewhat more targetted CC lists...
>
>> I also have not yet looked further into what exactly is happening and
>> whether or not the SPI stack, the Tegra SPI controller driver or the
>> MCP2515 SPI CAN driver is to blame but rather decided to ask Mr. Brown
>> and the community first for any insights they might have to share.
>> Anybody?
>
> I'd ask for trace logs but obviously we can't turn them on until boot
> has finished... Adding some trace in the relevant bits of code to try
> to see where it's deadlocking is the obvious first step.

FWIW: the mcp2515 driver is accessing the SPI bus during probe(). Seems
you have to instrument the SPI stack and/or host driver.

Marc

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