Hi,
I'm having hard time making a patch that would compile nouveau_backlight.o
only if CONFIG_BACKLIGHT_CLASS_DEVICE is y or m, and define just stubs
when it is n.
I'm trying this in the nouveau/linux-2.6 kernel tree, which is basically
2.6.31-rc2.
I attempted the following:
--- a/drivers/gpu/drm/nouveau/Makefile
+++ b/drivers/gpu/drm/nouveau/Makefile
@@ -8,7 +8,7 @@ nouveau-y := nouveau_drv.o nouveau_state.o nouveau_fifo.o nouveau_mem.o \
nouveau_sgdma.o nouveau_dma.o \
nouveau_bo.o nouveau_fence.o nouveau_gem.o nouveau_ttm.o \
nouveau_hw.o nouveau_calc.o nouveau_bios.o nouveau_i2c.o \
- nouveau_display.o nouveau_fbcon.o nouveau_backlight.o \
+ nouveau_display.o nouveau_fbcon.o \
nv04_timer.o \
nv04_mc.o nv40_mc.o nv50_mc.o \
nv04_fb.o nv10_fb.o nv40_fb.o \
@@ -19,8 +19,9 @@ nouveau-y := nouveau_drv.o nouveau_state.o nouveau_fifo.o nouveau_mem.o \
nv50_crtc.o nv50_dac.o nv50_sor.o nv50_connector.o \
nv50_cursor.o nv50_display.o nv50_fbcon.o \
nv04_display.o nv04_output.o nv04_crtc.o nv04_cursor.o \
- nv04_fbcon.o
+ nv04_fbcon.o
nouveau-$(CONFIG_COMPAT) += nouveau_ioc32.o
+nouveau-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += nouveau_backlight.o
obj-$(CONFIG_DRM_NOUVEAU)+= nouveau.o
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -708,8 +708,21 @@ extern int nouveau_dma_init(struct nouveau_channel *);
extern int nouveau_dma_wait(struct nouveau_channel *, int size);
/* nouveau_backlight.c */
+#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
extern int nouveau_backlight_init(struct drm_device *);
extern void nouveau_backlight_exit(struct drm_device *);
+#else
+static inline int nouveau_backlight_init(struct drm_device *dev)
+{
+ (void)dev;
+ return 0;
+}
+
+static inline void nouveau_backlight_exit(struct drm_device *dev)
+{
+ (void)dev;
+}
+#endif
When CONFIG_BACKLIGHT_CLASS_DEVICE=m this behaves as if it was n, i.e.
I get the stubs and no nouveau_backlight.o.
For CONFIG_BACKLIGHT_CLASS_DEVICE=y and n I get what I want.
What is the proper way to get m behave like y in this situation?
Oh, and should I use the following instead of (void)dev;?
static inline void nouveau_backlight_exit(struct drm_device *dev __used) { }
Please, Cc me.
Thanks.
--
Pekka Paalanen
http://www.iki.fi/pq/
On Sun, Jul 12, 2009 at 12:06:25AM +0300, Pekka Paalanen wrote:
> +#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
>
You need to test _MODULE for the symbol too... since it's necessary to
be able to distinguish between symbols which exist in the vmlinux, and
symbols which require a module to be loaded.
#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) &&
defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
should work.
regards, Kyle
On Sat, 11 Jul 2009 17:53:43 -0400
Kyle McMartin <[email protected]> wrote:
> On Sun, Jul 12, 2009 at 12:06:25AM +0300, Pekka Paalanen wrote:
> > +#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
> >
>
> You need to test _MODULE for the symbol too... since it's necessary to
> be able to distinguish between symbols which exist in the vmlinux, and
> symbols which require a module to be loaded.
>
> #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) &&
> defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
>
> should work.
Just || instead of &&, and yes, this is a solution for half of the problem,
thanks.
But what about the Makefile?
nouveau-y := nouveau_drv.o ...
nouveau-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += nouveau_backlight.o
obj-$(CONFIG_DRM_NOUVEAU)+= nouveau.o
With this, nouveau_backlight.o is not built if
CONFIG_BACKLIGHT_CLASS_DEVICE=m. Should I write:
nouveau-$(if $(findstring m,$(CONFIG_BACKLIGHT_CLASS_DEVICE)),y,n) += \
nouveau_backlight.o
which to me looks ugly, or add a new Kconfig boolean option that is
selected 'if CONFIG_BACKLIGHT_CLASS_DEVICE' and use that in both Makefile
and code, or is there a canonical way to do this?
Other code seems to deal with a similar situation by #ifdef'ing the
whole c-file contents. That cannot be the preferred way, can it?
Thanks.
--
Pekka Paalanen
http://www.iki.fi/pq/