Re: [PATCH] tty: Remove leftover dependencies on PPC_OF

[Kevin Hao]

On Fri, Apr 17, 2015 at 07:58:10AM +0100, Grant Likely wrote:
> On Fri, Apr 17, 2015 at 7:01 AM, Kevin Hao <haokexin@xxxxxxxxx> wrote:
> > On Thu, Apr 16, 2015 at 10:20:59PM -0700, Guenter Roeck wrote:
> >> powerpc qemu runs fail with the current upstream kernel.
> >> Bisect points to commit 52d996270032 ("powerpc: kill PPC_OF").
> >> Unfortunately, that commit did not remove all instances of PPC_OF.
> >> Practical impact is that the serial driver used by powerpc qemu
> >> targets is no longer built into the test kernel.
> >
> > Sorry for the break. This is a dependency issue. The patch 213dce3c17a6
> > ("tty: kconfig: remove the superfluous dependency on PPC_OF") has already
> > been merged into tty-next, but still not propagate to upstream yet. I failed
> > to reminder Michael of this when the pulling request is sent to Linus.
> 
> This means you're doing it wrong.

Definitely.

> If there are dependencies between
> patches, then they *must* all be in the same tree. You cannot depend
> on the order that branches get merged because it breaks bisecting.

We don't try to depend on the order that branches get merged. We just want to
merge the patch which kill the PPC_OF completely only after all the patches for
the specific drivers have been merged. I should took the responsibility to
make sure of this, but of course I missed something. Yes. putting all the
patches into the same tree should be a better plan. I will make sure of this
next time. :-)

> 
> Or, to put it another way, every branch must compile on it's own
> without needing to be merged into mainline or linux-next first.

This issue doesn't break compile. That is another reason we didn't find it
earlier.

Thanks,
Kevin

> 
> There are two ways to handle this. The easiest is to commit all the
> patches to a single branch. Then there is guaranteed to be no
> problems. However, if the patches really need to be split up between
> several branches, then the way to handle it is to put the prerequisite
> patches into a new clean branch, and then merge that branch into each
> tree that needs the prerequisite. That way every single tree includes
> the required commit without committing it more than once or breaking
> bisectability.
> 
> g.
> 
> >
> > Thanks,
> > Kevin
> >>
> >> Fixes: 52d996270032 ("powerpc: kill PPC_OF")
> >> Cc: Kevin Hao <haokexin@xxxxxxxxx>
> >> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> >> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> >> ---
> >>  drivers/tty/serial/Kconfig | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> >> index d2501f01cd03..77471d3db8d3 100644
> >> --- a/drivers/tty/serial/Kconfig
> >> +++ b/drivers/tty/serial/Kconfig
> >> @@ -835,7 +835,7 @@ config SERIAL_MCF_CONSOLE
> >>
> >>  config SERIAL_PMACZILOG
> >>       tristate "Mac or PowerMac z85c30 ESCC support"
> >> -     depends on (M68K && MAC) || (PPC_OF && PPC_PMAC)
> >> +     depends on (M68K && MAC) || PPC_PMAC
> >>       select SERIAL_CORE
> >>       help
> >>         This driver supports the Zilog z85C30 serial ports found on
> >> @@ -1153,7 +1153,7 @@ config SERIAL_OMAP_CONSOLE
> >>
> >>  config SERIAL_OF_PLATFORM_NWPSERIAL
> >>       tristate "NWP serial port driver"
> >> -     depends on PPC_OF && PPC_DCR
> >> +     depends on PPC_DCR
> >>       select SERIAL_OF_PLATFORM
> >>       select SERIAL_CORE_CONSOLE
> >>       select SERIAL_CORE
> >> --
> >> 2.1.0
> >>

Attachment: pgpopxAZudgPp.pgp
Description: PGP signature