Subject: Re: [PATCH] arm64: defconfig: Enable FSL_EDMA driver

From: Shawn Guo <[email-masked]>
Date: Tue, 18 Jun 2019 14:31:16 +0800

On Thu, Jun 13, 2019 at 02:01:11PM +0000, Leo Li wrote:
> 
> 
> > -----Original Message-----
> > From: Shawn Guo <[email-masked]>
> > Sent: Wednesday, June 12, 2019 7:45 PM
> > To: Leo Li <[email-masked]>
> > Cc: Madalin-cristian Bucur <[email-masked]>; Rob Herring
> > <[email-masked]>; Aisheng Dong <[email-masked]>; Vinod Koul
> > <[email-masked]>; Grant Likely <[email-masked]>; moderated
> > list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE <linux-arm-
> > [email-masked]>; lkml <[email-masked]>
> > Subject: Re: [PATCH] arm64: defconfig: Enable FSL_EDMA driver
> > 
> > On Wed, Jun 12, 2019 at 03:01:29PM -0500, Li Yang wrote:
> > > On Thu, May 9, 2019 at 10:15 PM Shawn Guo <[email-masked]>
> > wrote:
> > > >
> > > > On Mon, Apr 22, 2019 at 01:30:56PM -0500, Li Yang wrote:
> > > > > Enables the FSL EDMA driver by default.  This also works around an
> > > > > issue that imx-i2c driver keeps deferring the probe because of the
> > > > > DMA is not ready.  And currently the DMA engine framework can not
> > > > > correctly tell if the DMA channels will truly become available
> > > > > later (it will never be available if the DMA driver is not enabled).
> > > > >
> > > > > This will cause indefinite messages like below:
> > > > > [    3.335829] imx-i2c 2180000.i2c: can't get pinctrl, bus recovery not
> > supported
> > > > > [    3.344455] ina2xx 0-0040: power monitor ina220 (Rshunt = 1000
> > uOhm)
> > > > > [    3.350917] lm90 0-004c: 0-004c supply vcc not found, using dummy
> > regulator
> > > > > [    3.362089] imx-i2c 2180000.i2c: can't get pinctrl, bus recovery not
> > supported
> > > > > [    3.370741] ina2xx 0-0040: power monitor ina220 (Rshunt = 1000
> > uOhm)
> > > > > [    3.377205] lm90 0-004c: 0-004c supply vcc not found, using dummy
> > regulator
> > > > > [    3.388455] imx-i2c 2180000.i2c: can't get pinctrl, bus recovery not
> > supported
> > > > > .....
> > > > >
> > > > > Signed-off-by: Li Yang <[email-masked]>
> > > >
> > > > Applied, thanks.
> > >
> > > Hi Shawn,
> > >
> > > Is it possible to move this patch to the -fix series so that it can
> > > reach the mainline earlier?  It is having a boot failure in mainline
> > > for platforms using this device without this workaround.
> > 
> > Why would I2C device deferring cause boot failure on a platform?  I'm just
> > trying to understand severity of the problem.
> 
> Currently the probe of imx-i2c will be retried immediately after it is deferred when the optional dependency on DMA driver is not met.  This will cause an indefinite loop of probe-defer-probe and keep printing the message as shown in the commit message.
> 

Indefinite loop of probe-defer-probe is not a boot failure to me.  But I
will try to send it as fix, and see if arm-soc folk will take it.

Shawn

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