Re: linux 4.2-rc1 broken Nokia N900

[Pavel Machek <pavel@ucw.cz>]

On Tue 2015-07-14 11:33:42, Michael Welling wrote:
> On Tue, Jul 14, 2015 at 09:14:12AM +0200, Pali Rohár wrote:
> > On Monday 13 July 2015 17:36:07 Michael Welling wrote:
> > > On Tue, Jul 14, 2015 at 12:02:44AM +0200, Pali Rohár wrote:
> > > > I think nothing special. I just call:
> > > > 
> > > > export ARCH=arm
> > > > export CROSS_COMPILE=arm-linux-gnueabi-
> > > > make rx51_defconfig
> > > > rm -f arch/arm/boot/zImage
> > > > make -j12 zImage modules omap3-n900.dtb CONFIG_DEBUG_SECTION_MISMATCH=y
> > > > cat arch/arm/boot/zImage arch/arm/boot/dts/omap3-n900.dtb > arch/arm/boot/zImage.new
> > > > mv arch/arm/boot/zImage.new arch/arm/boot/zImage
> > > >
> > > 
> > > Where are you getting rx51_defconfig from?
> > > 
> > > This does not appear to be in the kernel source any longer.
> > > 
> > > Can you try the above with omap2plus_defconfig?
> > >  
> > 
> > It is in my linux-n900 repository: https://github.com/pali/linux-n900
> > Repository contains more n900 specific patches but SPI code is unpatched
> > 
> > https://github.com/pali/linux-n900/blob/HEAD/arch/arm/configs/rx51_defconfig
> > 
> > Later in week I can try to compile also with omap2plus_defconfig...
> > But in my opinion kernel should not crash with different configuration.
> 
> True.
> 
> Could you try the following change to the set_cs function and see if
>it helps.

Ok, so:

4.2-rc1 worked for me, IIRC.

4.2-rc2 oopses a lot.

4.2-rc2+ this patch oopses, too. I don't have serial console, so it is
hard to tell if it is the same oops.

									Pavel

> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 5867384..666038b 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -245,16 +245,18 @@ static void omap2_mcspi_set_enable(const struct spi_device *spi, int enable)
>  
>  static void omap2_mcspi_set_cs(struct spi_device *spi, bool enable)
>  {
> +	struct omap2_mcspi_cs *cs = spi->controller_state;
>  	u32 l;
>  
> -	/* The controller handles the inverted chip selects
> -	 * using the OMAP2_MCSPI_CHCONF_EPOL bit so revert
> -	 * the inversion from the core spi_set_cs function.
> -	 */
> -	if (spi->mode & SPI_CS_HIGH)
> -		enable = !enable;
> +	if (cs) {
> +
-- 
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