Nouveau - Jan 2015 - [PATCH nouveau 09/11] drm: export some variable and functions to resue the PM functions

On Tue, Dec 30, 2014 at 11:18:34AM +0800, Vince Hsu
wrote:
> Hi Emil,
> 
> On 12/30/2014 10:34 AM, Emil Velikov wrote:
> >On 23/12/14 10:40, Vince Hsu wrote:
> >>This patch adds some checks in the suspend/resume functions to
distinguish
> >>the dGPU and mobile GPU and exports some variables/functions so
that the
> >>nouveau platform device can reuse them.
> >>
> >Hi Vince,
> >
> >Afaiu one needs to export a symbol as it's used by another module
or
> >subsystem. With the follow up two patches you are not doing either one,
> >so I'd assume that you can just omit the EXPORT_* changes.
> The nouveau platform device driver is built as another module -
> nouveau_platform.ko. :)
I'd like to hear the opinion of the nouveau people and Alex, but I'd
very much prefer if nouveau_platform.o was simply linked into the
nouveau.ko module. I don't see any good reason to keep it separate.

Something like the attached patch (untested) ought to do it.

Thierry
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diff --git a/drivers/gpu/drm/nouveau/Kconfig b/drivers/gpu/drm/nouveau/Kconfig
index 40afc69a3778..5ab13e7939db 100644
--- a/drivers/gpu/drm/nouveau/Kconfig
+++ b/drivers/gpu/drm/nouveau/Kconfig
@@ -26,7 +26,7 @@ config DRM_NOUVEAU
 	  Choose this option for open-source NVIDIA support.
 
 config NOUVEAU_PLATFORM_DRIVER
-	tristate "Nouveau (NVIDIA) SoC GPUs"
+	bool "Nouveau (NVIDIA) SoC GPUs"
 	depends on DRM_NOUVEAU && ARCH_TEGRA
 	default y
 	help
diff --git a/drivers/gpu/drm/nouveau/Makefile b/drivers/gpu/drm/nouveau/Makefile
index ea40cd653c7c..13acf90c11c8 100644
--- a/drivers/gpu/drm/nouveau/Makefile
+++ b/drivers/gpu/drm/nouveau/Makefile
@@ -394,8 +394,6 @@ nouveau-$(CONFIG_ACPI) += nouveau_acpi.o
 endif
 nouveau-$(CONFIG_DRM_NOUVEAU_BACKLIGHT) += nouveau_backlight.o
 nouveau-$(CONFIG_DEBUG_FS) += nouveau_debugfs.o
+nouveau-$(CONFIG_NOUVEAU_PLATFORM_DRIVER) += nouveau_platform.o
 
 obj-$(CONFIG_DRM_NOUVEAU)+= nouveau.o
-
-# platform driver
-obj-$(CONFIG_NOUVEAU_PLATFORM_DRIVER) += nouveau_platform.o
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On Mon, Jan 5, 2015 at 4:32 PM, Thierry Reding <thierry.reding at
gmail.com> wrote:
> On Tue, Dec 30, 2014 at 11:18:34AM +0800, Vince Hsu wrote:
>> Hi Emil,
>>
>> On 12/30/2014 10:34 AM, Emil Velikov wrote:
>> >On 23/12/14 10:40, Vince Hsu wrote:
>> >>This patch adds some checks in the suspend/resume functions to
distinguish
>> >>the dGPU and mobile GPU and exports some variables/functions so
that the
>> >>nouveau platform device can reuse them.
>> >>
>> >Hi Vince,
>> >
>> >Afaiu one needs to export a symbol as it's used by another
module or
>> >subsystem. With the follow up two patches you are not doing either
one,
>> >so I'd assume that you can just omit the EXPORT_* changes.
>> The nouveau platform device driver is built as another module -
>> nouveau_platform.ko. :)
>
> I'd like to hear the opinion of the nouveau people and Alex, but
I'd
> very much prefer if nouveau_platform.o was simply linked into the
> nouveau.ko module. I don't see any good reason to keep it separate.
Yep, I agree. The decision to host platform support in a separate
module looks misleaded if it results in additional exports that we
would otherwise avoid. IIUC I did this to be able to use the module
convenience macros to register the platform driver.
>
> Something like the attached patch (untested) ought to do it.
This patch alone won't be enough for the reason I mentioned above.
However, if Vince doesn't mind handling the platform driver
registration manually in nouveau_drm_init/nouveau_drm_exit, I agree
this would be the way to go.

Cheers,
Alex.

On 01/06/2015 03:50 AM, Alexandre Courbot wrote:
> On Mon, Jan 5, 2015 at 4:32 PM, Thierry Reding <thierry.reding at
gmail.com> wrote:
>> On Tue, Dec 30, 2014 at 11:18:34AM +0800, Vince Hsu wrote:
>>> Hi Emil,
>>>
>>> On 12/30/2014 10:34 AM, Emil Velikov wrote:
>>>> On 23/12/14 10:40, Vince Hsu wrote:
>>>>> This patch adds some checks in the suspend/resume functions
to distinguish
>>>>> the dGPU and mobile GPU and exports some
variables/functions so that the
>>>>> nouveau platform device can reuse them.
>>>>>
>>>> Hi Vince,
>>>>
>>>> Afaiu one needs to export a symbol as it's used by another
module or
>>>> subsystem. With the follow up two patches you are not doing
either one,
>>>> so I'd assume that you can just omit the EXPORT_* changes.
>>> The nouveau platform device driver is built as another module -
>>> nouveau_platform.ko. :)
>> I'd like to hear the opinion of the nouveau people and Alex, but
I'd
>> very much prefer if nouveau_platform.o was simply linked into the
>> nouveau.ko module. I don't see any good reason to keep it separate.
> Yep, I agree. The decision to host platform support in a separate
> module looks misleaded if it results in additional exports that we
> would otherwise avoid. IIUC I did this to be able to use the module
> convenience macros to register the platform driver.
>
>> Something like the attached patch (untested) ought to do it.
> This patch alone won't be enough for the reason I mentioned above.
> However, if Vince doesn't mind handling the platform driver
> registration manually in nouveau_drm_init/nouveau_drm_exit, I agree
> this would be the way to go.
I definitely don't mind. :) Will fix in next version based on you guys' 
suggestions.

Thanks,
Vince

On Mon, Jan 05, 2015 at 08:50:18PM +0100, Alexandre Courbot
wrote:
> On Mon, Jan 5, 2015 at 4:32 PM, Thierry Reding <thierry.reding at
gmail.com> wrote:
> > On Tue, Dec 30, 2014 at 11:18:34AM +0800, Vince Hsu wrote:
> >> Hi Emil,
> >>
> >> On 12/30/2014 10:34 AM, Emil Velikov wrote:
> >> >On 23/12/14 10:40, Vince Hsu wrote:
> >> >>This patch adds some checks in the suspend/resume
functions to distinguish
> >> >>the dGPU and mobile GPU and exports some
variables/functions so that the
> >> >>nouveau platform device can reuse them.
> >> >>
> >> >Hi Vince,
> >> >
> >> >Afaiu one needs to export a symbol as it's used by another
module or
> >> >subsystem. With the follow up two patches you are not doing
either one,
> >> >so I'd assume that you can just omit the EXPORT_* changes.
> >> The nouveau platform device driver is built as another module -
> >> nouveau_platform.ko. :)
> >
> > I'd like to hear the opinion of the nouveau people and Alex, but
I'd
> > very much prefer if nouveau_platform.o was simply linked into the
> > nouveau.ko module. I don't see any good reason to keep it
separate.
> 
> Yep, I agree. The decision to host platform support in a separate
> module looks misleaded if it results in additional exports that we
> would otherwise avoid. IIUC I did this to be able to use the module
> convenience macros to register the platform driver.
> 
> >
> > Something like the attached patch (untested) ought to do it.
> 
> This patch alone won't be enough for the reason I mentioned above.
> However, if Vince doesn't mind handling the platform driver
> registration manually in nouveau_drm_init/nouveau_drm_exit, I agree
> this would be the way to go.
If we do the conversion to generic power domains, the only Tegra-
specific API remaining will be the access to the fuse registers for the
speedo value. At that point we wouldn't need the ARCH_TEGRA dependency
any longer and could always build the platform driver along with the PCI
driver.

I guess we could do that even now if we simply #ifdef the various Tegra-
specific parts. That in turn would have the advantage that we don't need
to #ifdef the driver registration code. And it would help separate
things in case anybody wanted to use one of the SoC GPUs in a non-Tegra
SoC.

Thierry
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