| Message ID | 20190501233815.32643-15-digetx@gmail.com |
|---|---|
| State | Deferred |
| Headers | show |
| Series | NVIDIA Tegra devfreq improvements and Tegra20/30 support | expand |
On Thu, May 02, 2019 at 02:38:13AM +0300, Dmitry Osipenko wrote: > The driver's compilation doesn't have any specific dependencies, hence > the COMPILE_TEST option can be supported in Kconfig. > > Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> > Signed-off-by: Dmitry Osipenko <digetx@gmail.com> > --- > drivers/devfreq/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > index 56db9dc05edb..a6bba6e1e7d9 100644 > --- a/drivers/devfreq/Kconfig > +++ b/drivers/devfreq/Kconfig > @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ > > config ARM_TEGRA_DEVFREQ > tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" > - depends on ARCH_TEGRA > + depends on ARCH_TEGRA || COMPILE_TEST > select PM_OPP > help > This adds the DEVFREQ driver for the Tegra family of SoCs. You need to be careful with these. You're using I/O register accessors, which are not supported on the UM architecture, for example. This may end up getting flagged during build testing. Thierry
04.06.2019 14:20, Thierry Reding пишет: > On Thu, May 02, 2019 at 02:38:13AM +0300, Dmitry Osipenko wrote: >> The driver's compilation doesn't have any specific dependencies, hence >> the COMPILE_TEST option can be supported in Kconfig. >> >> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> >> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> >> --- >> drivers/devfreq/Kconfig | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig >> index 56db9dc05edb..a6bba6e1e7d9 100644 >> --- a/drivers/devfreq/Kconfig >> +++ b/drivers/devfreq/Kconfig >> @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ >> >> config ARM_TEGRA_DEVFREQ >> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" >> - depends on ARCH_TEGRA >> + depends on ARCH_TEGRA || COMPILE_TEST >> select PM_OPP >> help >> This adds the DEVFREQ driver for the Tegra family of SoCs. > > You need to be careful with these. You're using I/O register accessors, > which are not supported on the UM architecture, for example. > > This may end up getting flagged during build testing. We have similar cases in other drivers and it doesn't cause any known problems because (I think) build-bots are aware of this detail. Hence there is no real need to be overreactive here and in this particular case it's better to react to real problems once they show up (we already did that by fixing build breakage caused by a CLK API problem found by bot in v3). Does it sound like a good argument to you? ACK?
On Tue, Jun 04, 2019 at 04:53:17PM +0300, Dmitry Osipenko wrote: > 04.06.2019 14:20, Thierry Reding пишет: > > On Thu, May 02, 2019 at 02:38:13AM +0300, Dmitry Osipenko wrote: > >> The driver's compilation doesn't have any specific dependencies, hence > >> the COMPILE_TEST option can be supported in Kconfig. > >> > >> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> > >> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> > >> --- > >> drivers/devfreq/Kconfig | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > >> index 56db9dc05edb..a6bba6e1e7d9 100644 > >> --- a/drivers/devfreq/Kconfig > >> +++ b/drivers/devfreq/Kconfig > >> @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ > >> > >> config ARM_TEGRA_DEVFREQ > >> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" > >> - depends on ARCH_TEGRA > >> + depends on ARCH_TEGRA || COMPILE_TEST > >> select PM_OPP > >> help > >> This adds the DEVFREQ driver for the Tegra family of SoCs. > > > > You need to be careful with these. You're using I/O register accessors, > > which are not supported on the UM architecture, for example. > > > > This may end up getting flagged during build testing. > > We have similar cases in other drivers and it doesn't cause any known > problems because (I think) build-bots are aware of this detail. Hence I don't understand how the build-bots would be aware of this detail. Unless you explicitly state what the dependencies are, how would the build-bots know? Perhaps there's some logic built-in somewhere that I don't know about? > there is no real need to be overreactive here and in this particular > case it's better to react to real problems once they show up (we already > did that by fixing build breakage caused by a CLK API problem found by > bot in v3). Does it sound like a good argument to you? ACK? No. This strikes me as a strange argument. I'm pointing out a potential source of problems and you just brush it aside claiming that it's not true, or even if it was true that we'll see eventually and we can fix it up when there's an actual problem. Why would you want to have to fix things up if you can avoid breakage in the first place by being a little proactive? Thierry
On Tue, Jun 04, 2019 at 04:10:31PM +0200, Thierry Reding wrote: > On Tue, Jun 04, 2019 at 04:53:17PM +0300, Dmitry Osipenko wrote: > > 04.06.2019 14:20, Thierry Reding пишет: > > > On Thu, May 02, 2019 at 02:38:13AM +0300, Dmitry Osipenko wrote: > > >> The driver's compilation doesn't have any specific dependencies, hence > > >> the COMPILE_TEST option can be supported in Kconfig. > > >> > > >> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> > > >> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> > > >> --- > > >> drivers/devfreq/Kconfig | 2 +- > > >> 1 file changed, 1 insertion(+), 1 deletion(-) > > >> > > >> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > > >> index 56db9dc05edb..a6bba6e1e7d9 100644 > > >> --- a/drivers/devfreq/Kconfig > > >> +++ b/drivers/devfreq/Kconfig > > >> @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ > > >> > > >> config ARM_TEGRA_DEVFREQ > > >> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" > > >> - depends on ARCH_TEGRA > > >> + depends on ARCH_TEGRA || COMPILE_TEST > > >> select PM_OPP > > >> help > > >> This adds the DEVFREQ driver for the Tegra family of SoCs. > > > > > > You need to be careful with these. You're using I/O register accessors, > > > which are not supported on the UM architecture, for example. > > > > > > This may end up getting flagged during build testing. > > > > We have similar cases in other drivers and it doesn't cause any known > > problems because (I think) build-bots are aware of this detail. Hence > > I don't understand how the build-bots would be aware of this detail. > Unless you explicitly state what the dependencies are, how would the > build-bots know? Perhaps there's some logic built-in somewhere that I > don't know about? So looks like COMPILE_TEST has a !UML dependency, so this might just work. Acked-by: Thierry Reding <treding@nvidia.com>
04.06.2019 17:18, Thierry Reding пишет: > On Tue, Jun 04, 2019 at 04:10:31PM +0200, Thierry Reding wrote: >> On Tue, Jun 04, 2019 at 04:53:17PM +0300, Dmitry Osipenko wrote: >>> 04.06.2019 14:20, Thierry Reding пишет: >>>> On Thu, May 02, 2019 at 02:38:13AM +0300, Dmitry Osipenko wrote: >>>>> The driver's compilation doesn't have any specific dependencies, hence >>>>> the COMPILE_TEST option can be supported in Kconfig. >>>>> >>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> >>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> >>>>> --- >>>>> drivers/devfreq/Kconfig | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig >>>>> index 56db9dc05edb..a6bba6e1e7d9 100644 >>>>> --- a/drivers/devfreq/Kconfig >>>>> +++ b/drivers/devfreq/Kconfig >>>>> @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ >>>>> >>>>> config ARM_TEGRA_DEVFREQ >>>>> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" >>>>> - depends on ARCH_TEGRA >>>>> + depends on ARCH_TEGRA || COMPILE_TEST >>>>> select PM_OPP >>>>> help >>>>> This adds the DEVFREQ driver for the Tegra family of SoCs. >>>> >>>> You need to be careful with these. You're using I/O register accessors, >>>> which are not supported on the UM architecture, for example. >>>> >>>> This may end up getting flagged during build testing. >>> >>> We have similar cases in other drivers and it doesn't cause any known >>> problems because (I think) build-bots are aware of this detail. Hence >> >> I don't understand how the build-bots would be aware of this detail. >> Unless you explicitly state what the dependencies are, how would the >> build-bots know? Perhaps there's some logic built-in somewhere that I >> don't know about? > > So looks like COMPILE_TEST has a !UML dependency, so this might just > work. > > Acked-by: Thierry Reding <treding@nvidia.com> > Thank you very much for the clarification! Certainly that would caused problems already since there are such cases all over the kernel, including Tegra drivers.
On Tue, Jun 04, 2019 at 05:41:53PM +0300, Dmitry Osipenko wrote: > 04.06.2019 17:18, Thierry Reding пишет: > > On Tue, Jun 04, 2019 at 04:10:31PM +0200, Thierry Reding wrote: > >> On Tue, Jun 04, 2019 at 04:53:17PM +0300, Dmitry Osipenko wrote: > >>> 04.06.2019 14:20, Thierry Reding пишет: > >>>> On Thu, May 02, 2019 at 02:38:13AM +0300, Dmitry Osipenko wrote: > >>>>> The driver's compilation doesn't have any specific dependencies, hence > >>>>> the COMPILE_TEST option can be supported in Kconfig. > >>>>> > >>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> > >>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> > >>>>> --- > >>>>> drivers/devfreq/Kconfig | 2 +- > >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig > >>>>> index 56db9dc05edb..a6bba6e1e7d9 100644 > >>>>> --- a/drivers/devfreq/Kconfig > >>>>> +++ b/drivers/devfreq/Kconfig > >>>>> @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ > >>>>> > >>>>> config ARM_TEGRA_DEVFREQ > >>>>> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" > >>>>> - depends on ARCH_TEGRA > >>>>> + depends on ARCH_TEGRA || COMPILE_TEST > >>>>> select PM_OPP > >>>>> help > >>>>> This adds the DEVFREQ driver for the Tegra family of SoCs. > >>>> > >>>> You need to be careful with these. You're using I/O register accessors, > >>>> which are not supported on the UM architecture, for example. > >>>> > >>>> This may end up getting flagged during build testing. > >>> > >>> We have similar cases in other drivers and it doesn't cause any known > >>> problems because (I think) build-bots are aware of this detail. Hence > >> > >> I don't understand how the build-bots would be aware of this detail. > >> Unless you explicitly state what the dependencies are, how would the > >> build-bots know? Perhaps there's some logic built-in somewhere that I > >> don't know about? > > > > So looks like COMPILE_TEST has a !UML dependency, so this might just > > work. > > > > Acked-by: Thierry Reding <treding@nvidia.com> > > > > Thank you very much for the clarification! Certainly that would caused > problems already since there are such cases all over the kernel, > including Tegra drivers. In the cases that I'm aware of we used to explicitly list all the dependencies that would've otherwise been pulled in by the ARCH_TEGRA dependency to make sure there were no issues. Now that we've been discussing this I vaguely recall a discussion about the only real issue nowadays being HAS_IOMEM and since that's only missing on UML, that may have been the reason for why the !UML dependency was added. Yes, looks like that was it: commit bc083a64b6c035135c0f80718f9e9192cc0867c6 Author: Richard Weinberger <richard@nod.at> Date: Tue Aug 2 14:03:27 2016 -0700 init/Kconfig: make COMPILE_TEST depend on !UML UML is a bit special since it does not have iomem nor dma. That means a lot of drivers will not build if they miss a dependency on HAS_IOMEM. s390 used to have the same issues but since it gained PCI support UML is the only stranger. We are tired of patching dozens of new drivers after every merge window just to un-break allmod/yesconfig UML builds. One could argue that a decent driver has to know on what it depends and therefore a missing HAS_IOMEM dependency is a clear driver bug. But the dependency not obvious and not everyone does UML builds with COMPILE_TEST enabled when developing a device driver. A possible solution to make these builds succeed on UML would be providing stub functions for ioremap() and friends which fail upon runtime. Another one is simply disabling COMPILE_TEST for UML. Since it is the least hassle and does not force use to fake iomem support let's do the latter. Link: http://lkml.kernel.org/r/1466152995-28367-1-git-send-email-richard@nod.at Signed-off-by: Richard Weinberger <richard@nod.at> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Oh wow... almost three years now. Thierry
04.06.2019 17:50, Thierry Reding пишет: > On Tue, Jun 04, 2019 at 05:41:53PM +0300, Dmitry Osipenko wrote: >> 04.06.2019 17:18, Thierry Reding пишет: >>> On Tue, Jun 04, 2019 at 04:10:31PM +0200, Thierry Reding wrote: >>>> On Tue, Jun 04, 2019 at 04:53:17PM +0300, Dmitry Osipenko wrote: >>>>> 04.06.2019 14:20, Thierry Reding пишет: >>>>>> On Thu, May 02, 2019 at 02:38:13AM +0300, Dmitry Osipenko wrote: >>>>>>> The driver's compilation doesn't have any specific dependencies, hence >>>>>>> the COMPILE_TEST option can be supported in Kconfig. >>>>>>> >>>>>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> >>>>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> >>>>>>> --- >>>>>>> drivers/devfreq/Kconfig | 2 +- >>>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>>> >>>>>>> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig >>>>>>> index 56db9dc05edb..a6bba6e1e7d9 100644 >>>>>>> --- a/drivers/devfreq/Kconfig >>>>>>> +++ b/drivers/devfreq/Kconfig >>>>>>> @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ >>>>>>> >>>>>>> config ARM_TEGRA_DEVFREQ >>>>>>> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" >>>>>>> - depends on ARCH_TEGRA >>>>>>> + depends on ARCH_TEGRA || COMPILE_TEST >>>>>>> select PM_OPP >>>>>>> help >>>>>>> This adds the DEVFREQ driver for the Tegra family of SoCs. >>>>>> >>>>>> You need to be careful with these. You're using I/O register accessors, >>>>>> which are not supported on the UM architecture, for example. >>>>>> >>>>>> This may end up getting flagged during build testing. >>>>> >>>>> We have similar cases in other drivers and it doesn't cause any known >>>>> problems because (I think) build-bots are aware of this detail. Hence >>>> >>>> I don't understand how the build-bots would be aware of this detail. >>>> Unless you explicitly state what the dependencies are, how would the >>>> build-bots know? Perhaps there's some logic built-in somewhere that I >>>> don't know about? >>> >>> So looks like COMPILE_TEST has a !UML dependency, so this might just >>> work. >>> >>> Acked-by: Thierry Reding <treding@nvidia.com> >>> >> >> Thank you very much for the clarification! Certainly that would caused >> problems already since there are such cases all over the kernel, >> including Tegra drivers. > > In the cases that I'm aware of we used to explicitly list all the > dependencies that would've otherwise been pulled in by the ARCH_TEGRA > dependency to make sure there were no issues. > > Now that we've been discussing this I vaguely recall a discussion about > the only real issue nowadays being HAS_IOMEM and since that's only > missing on UML, that may have been the reason for why the !UML > dependency was added. > > Yes, looks like that was it: > > commit bc083a64b6c035135c0f80718f9e9192cc0867c6 > Author: Richard Weinberger <richard@nod.at> > Date: Tue Aug 2 14:03:27 2016 -0700 > > init/Kconfig: make COMPILE_TEST depend on !UML > > UML is a bit special since it does not have iomem nor dma. That means a > lot of drivers will not build if they miss a dependency on HAS_IOMEM. > s390 used to have the same issues but since it gained PCI support UML is > the only stranger. > > We are tired of patching dozens of new drivers after every merge window > just to un-break allmod/yesconfig UML builds. One could argue that a > decent driver has to know on what it depends and therefore a missing > HAS_IOMEM dependency is a clear driver bug. But the dependency not > obvious and not everyone does UML builds with COMPILE_TEST enabled when > developing a device driver. > > A possible solution to make these builds succeed on UML would be > providing stub functions for ioremap() and friends which fail upon > runtime. Another one is simply disabling COMPILE_TEST for UML. Since > it is the least hassle and does not force use to fake iomem support > let's do the latter. > > Link: http://lkml.kernel.org/r/1466152995-28367-1-git-send-email-richard@nod.at > Signed-off-by: Richard Weinberger <richard@nod.at> > Acked-by: Arnd Bergmann <arnd@arndb.de> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> That was a wise solution. Thank you very much again for the detailed comment! Very appreciate that! > Oh wow... almost three years now. Please don't pay much attention to the time, it never stops. Live in the moment :)
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig index 56db9dc05edb..a6bba6e1e7d9 100644 --- a/drivers/devfreq/Kconfig +++ b/drivers/devfreq/Kconfig @@ -93,7 +93,7 @@ config ARM_EXYNOS_BUS_DEVFREQ config ARM_TEGRA_DEVFREQ tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" - depends on ARCH_TEGRA + depends on ARCH_TEGRA || COMPILE_TEST select PM_OPP help This adds the DEVFREQ driver for the Tegra family of SoCs.