[PATCH 1/2] drm/i915/display: fix randconfig build

[PATCH 1/2] drm/i915/display: fix randconfig build

[Jiri Slaby (SUSE)]

When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'

ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'

To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
with the above config, backlight support is disabled.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Reported-by: Martin Liška <mliska@suse.cz>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
 drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
index beba39a38c87..c1ba68796b6d 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
 	mutex_unlock(&dev_priv->display.backlight.lock);
 }
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 static u32 intel_panel_get_backlight(struct intel_connector *connector)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
index 339643f63897..207fe1c613d8 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.h
+++ b/drivers/gpu/drm/i915/display/intel_backlight.h
@@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
 u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
 u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 int intel_backlight_device_register(struct intel_connector *connector);
 void intel_backlight_device_unregister(struct intel_connector *connector);
 #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
-- 
2.37.3

[PATCH 1/2] drm/i915/display: fix randconfig build

[Jiri Slaby (SUSE)]

When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'

ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'

To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
with the above config, backlight support is disabled.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Reported-by: Martin Liška <mliska@suse.cz>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
 drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
index beba39a38c87..c1ba68796b6d 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
 	mutex_unlock(&dev_priv->display.backlight.lock);
 }
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 static u32 intel_panel_get_backlight(struct intel_connector *connector)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
index 339643f63897..207fe1c613d8 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.h
+++ b/drivers/gpu/drm/i915/display/intel_backlight.h
@@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
 u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
 u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 int intel_backlight_device_register(struct intel_connector *connector);
 void intel_backlight_device_unregister(struct intel_connector *connector);
 #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
-- 
2.37.3

[Intel-gfx] [PATCH 1/2] drm/i915/display: fix randconfig build

[Jiri Slaby (SUSE)]

When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'

ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'

To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
with the above config, backlight support is disabled.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Reported-by: Martin Liška <mliska@suse.cz>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
 drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
index beba39a38c87..c1ba68796b6d 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
 	mutex_unlock(&dev_priv->display.backlight.lock);
 }
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 static u32 intel_panel_get_backlight(struct intel_connector *connector)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
index 339643f63897..207fe1c613d8 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.h
+++ b/drivers/gpu/drm/i915/display/intel_backlight.h
@@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
 u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
 u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 int intel_backlight_device_register(struct intel_connector *connector);
 void intel_backlight_device_unregister(struct intel_connector *connector);
 #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
-- 
2.37.3

[PATCH 2/2] drm/i915: remove circ_buf.h includes

[Jiri Slaby (SUSE)]

The last user of macros from that include was removed in 2018 by the
commit below.

Fixes: 6cc42152b02b ("drm/i915: Remove support for legacy debugfs crc interface")
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_pipe_crc.c | 1 -
 drivers/gpu/drm/i915/i915_irq.c               | 1 -
 2 files changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_pipe_crc.c b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
index 8ac263f471be..9070935b0443 100644
--- a/drivers/gpu/drm/i915/display/intel_pipe_crc.c
+++ b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
@@ -24,7 +24,6 @@
  *
  */
 
-#include <linux/circ_buf.h>
 #include <linux/ctype.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 86a42d9e8041..09d728b34a47 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -28,7 +28,6 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/circ_buf.h>
 #include <linux/slab.h>
 #include <linux/sysrq.h>
 
-- 
2.37.3

[PATCH 2/2] drm/i915: remove circ_buf.h includes

[Jiri Slaby (SUSE)]

The last user of macros from that include was removed in 2018 by the
commit below.

Fixes: 6cc42152b02b ("drm/i915: Remove support for legacy debugfs crc interface")
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_pipe_crc.c | 1 -
 drivers/gpu/drm/i915/i915_irq.c               | 1 -
 2 files changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_pipe_crc.c b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
index 8ac263f471be..9070935b0443 100644
--- a/drivers/gpu/drm/i915/display/intel_pipe_crc.c
+++ b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
@@ -24,7 +24,6 @@
  *
  */
 
-#include <linux/circ_buf.h>
 #include <linux/ctype.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 86a42d9e8041..09d728b34a47 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -28,7 +28,6 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/circ_buf.h>
 #include <linux/slab.h>
 #include <linux/sysrq.h>
 
-- 
2.37.3

[Intel-gfx] [PATCH 2/2] drm/i915: remove circ_buf.h includes

[Jiri Slaby (SUSE)]

The last user of macros from that include was removed in 2018 by the
commit below.

Fixes: 6cc42152b02b ("drm/i915: Remove support for legacy debugfs crc interface")
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_pipe_crc.c | 1 -
 drivers/gpu/drm/i915/i915_irq.c               | 1 -
 2 files changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_pipe_crc.c b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
index 8ac263f471be..9070935b0443 100644
--- a/drivers/gpu/drm/i915/display/intel_pipe_crc.c
+++ b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
@@ -24,7 +24,6 @@
  *
  */
 
-#include <linux/circ_buf.h>
 #include <linux/ctype.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 86a42d9e8041..09d728b34a47 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -28,7 +28,6 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/circ_buf.h>
 #include <linux/slab.h>
 #include <linux/sysrq.h>
 
-- 
2.37.3

Re: [PATCH 1/2] drm/i915/display: fix randconfig build

[Jani Nikula]

On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>
> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>
> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
> with the above config, backlight support is disabled.

So I don't want this. I'll take a patch that fixes the dependencies to
block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
and IMO using IS_REACHABLE() is a workaround to hide a broken config
under the carpet.

The right thing to do is

config DRM_I915
	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.

We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
too, and a combo of selecting and depending leads to circular
dependencies. But depending is the right fix.

Documentation/kbuild/kconfig-language.rst:

  Note:
	select should be used with care. select will force
	a symbol to a value without visiting the dependencies.
	By abusing select you are able to select a symbol FOO even
	if FOO depends on BAR that is not set.
	In general use select only for non-visible symbols
	(no prompts anywhere) and for symbols with no dependencies.
	That will limit the usefulness but on the other hand avoid
	the illegal configurations all over.


BR,
Jani.

>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Reported-by: Martin Liška <mliska@suse.cz>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> ---
>  drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>  drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
> index beba39a38c87..c1ba68796b6d 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>  	mutex_unlock(&dev_priv->display.backlight.lock);
>  }
>  
> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>  static u32 intel_panel_get_backlight(struct intel_connector *connector)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
> index 339643f63897..207fe1c613d8 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>  u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>  u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>  
> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>  int intel_backlight_device_register(struct intel_connector *connector);
>  void intel_backlight_device_unregister(struct intel_connector *connector);
>  #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [Intel-gfx] [PATCH 1/2] drm/i915/display: fix randconfig build

[Jani Nikula]

On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>
> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>
> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
> with the above config, backlight support is disabled.

So I don't want this. I'll take a patch that fixes the dependencies to
block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
and IMO using IS_REACHABLE() is a workaround to hide a broken config
under the carpet.

The right thing to do is

config DRM_I915
	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.

We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
too, and a combo of selecting and depending leads to circular
dependencies. But depending is the right fix.

Documentation/kbuild/kconfig-language.rst:

  Note:
	select should be used with care. select will force
	a symbol to a value without visiting the dependencies.
	By abusing select you are able to select a symbol FOO even
	if FOO depends on BAR that is not set.
	In general use select only for non-visible symbols
	(no prompts anywhere) and for symbols with no dependencies.
	That will limit the usefulness but on the other hand avoid
	the illegal configurations all over.


BR,
Jani.

>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Reported-by: Martin Liška <mliska@suse.cz>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> ---
>  drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>  drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
> index beba39a38c87..c1ba68796b6d 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>  	mutex_unlock(&dev_priv->display.backlight.lock);
>  }
>  
> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>  static u32 intel_panel_get_backlight(struct intel_connector *connector)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
> index 339643f63897..207fe1c613d8 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>  u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>  u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>  
> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>  int intel_backlight_device_register(struct intel_connector *connector);
>  void intel_backlight_device_unregister(struct intel_connector *connector);
>  #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [PATCH 1/2] drm/i915/display: fix randconfig build

[Jani Nikula]

On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>
> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>
> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
> with the above config, backlight support is disabled.

So I don't want this. I'll take a patch that fixes the dependencies to
block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
and IMO using IS_REACHABLE() is a workaround to hide a broken config
under the carpet.

The right thing to do is

config DRM_I915
	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.

We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
too, and a combo of selecting and depending leads to circular
dependencies. But depending is the right fix.

Documentation/kbuild/kconfig-language.rst:

  Note:
	select should be used with care. select will force
	a symbol to a value without visiting the dependencies.
	By abusing select you are able to select a symbol FOO even
	if FOO depends on BAR that is not set.
	In general use select only for non-visible symbols
	(no prompts anywhere) and for symbols with no dependencies.
	That will limit the usefulness but on the other hand avoid
	the illegal configurations all over.


BR,
Jani.

>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Reported-by: Martin Liška <mliska@suse.cz>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> ---
>  drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>  drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
> index beba39a38c87..c1ba68796b6d 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>  	mutex_unlock(&dev_priv->display.backlight.lock);
>  }
>  
> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>  static u32 intel_panel_get_backlight(struct intel_connector *connector)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
> index 339643f63897..207fe1c613d8 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>  u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>  u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>  
> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>  int intel_backlight_device_register(struct intel_connector *connector);
>  void intel_backlight_device_unregister(struct intel_connector *connector);
>  #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [PATCH 2/2] drm/i915: remove circ_buf.h includes

[Jani Nikula]

On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
> The last user of macros from that include was removed in 2018 by the
> commit below.
>
> Fixes: 6cc42152b02b ("drm/i915: Remove support for legacy debugfs crc interface")
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_pipe_crc.c | 1 -
>  drivers/gpu/drm/i915/i915_irq.c               | 1 -
>  2 files changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_pipe_crc.c b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> index 8ac263f471be..9070935b0443 100644
> --- a/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> +++ b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> @@ -24,7 +24,6 @@
>   *
>   */
>  
> -#include <linux/circ_buf.h>
>  #include <linux/ctype.h>
>  #include <linux/debugfs.h>
>  #include <linux/seq_file.h>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 86a42d9e8041..09d728b34a47 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -28,7 +28,6 @@
>  
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
> -#include <linux/circ_buf.h>
>  #include <linux/slab.h>
>  #include <linux/sysrq.h>

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [PATCH 2/2] drm/i915: remove circ_buf.h includes

[Jani Nikula]

On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
> The last user of macros from that include was removed in 2018 by the
> commit below.
>
> Fixes: 6cc42152b02b ("drm/i915: Remove support for legacy debugfs crc interface")
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_pipe_crc.c | 1 -
>  drivers/gpu/drm/i915/i915_irq.c               | 1 -
>  2 files changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_pipe_crc.c b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> index 8ac263f471be..9070935b0443 100644
> --- a/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> +++ b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> @@ -24,7 +24,6 @@
>   *
>   */
>  
> -#include <linux/circ_buf.h>
>  #include <linux/ctype.h>
>  #include <linux/debugfs.h>
>  #include <linux/seq_file.h>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 86a42d9e8041..09d728b34a47 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -28,7 +28,6 @@
>  
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
> -#include <linux/circ_buf.h>
>  #include <linux/slab.h>
>  #include <linux/sysrq.h>

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [Intel-gfx] [PATCH 2/2] drm/i915: remove circ_buf.h includes

[Jani Nikula]

On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
> The last user of macros from that include was removed in 2018 by the
> commit below.
>
> Fixes: 6cc42152b02b ("drm/i915: Remove support for legacy debugfs crc interface")
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_pipe_crc.c | 1 -
>  drivers/gpu/drm/i915/i915_irq.c               | 1 -
>  2 files changed, 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_pipe_crc.c b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> index 8ac263f471be..9070935b0443 100644
> --- a/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> +++ b/drivers/gpu/drm/i915/display/intel_pipe_crc.c
> @@ -24,7 +24,6 @@
>   *
>   */
>  
> -#include <linux/circ_buf.h>
>  #include <linux/ctype.h>
>  #include <linux/debugfs.h>
>  #include <linux/seq_file.h>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 86a42d9e8041..09d728b34a47 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -28,7 +28,6 @@
>  
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
> -#include <linux/circ_buf.h>
>  #include <linux/slab.h>
>  #include <linux/sysrq.h>

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [PATCH 1/2] drm/i915/display: fix randconfig build

[Jiri Slaby]

On 04. 10. 22, 12:52, Jani Nikula wrote:
> On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
>> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
>> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>>
>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
>> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>>
>> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
>> with the above config, backlight support is disabled.
> 
> So I don't want this. I'll take a patch that fixes the dependencies to
> block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
> and IMO using IS_REACHABLE() is a workaround to hide a broken config
> under the carpet.
> 
> The right thing to do is
> 
> config DRM_I915
> 	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.
> 
> We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
> too, and a combo of selecting and depending leads to circular
> dependencies. But depending is the right fix.

I'm not sure what should I do now. If I do:
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -4,6 +4,7 @@ config DRM_I915
         depends on DRM
         depends on X86 && PCI
         depends on !PREEMPT_RT
+       depends on (BACKLIGHT_CLASS_DEVICE && ACPI) || 
(BACKLIGHT_CLASS_DEVICE=n && ACPI=n)
         select INTEL_GTT if X86
         select INTERVAL_TREE
         # we need shmfs for the swappable backing store, and in particular
@@ -21,7 +22,6 @@ config DRM_I915
         select IRQ_WORK
         # i915 depends on ACPI_VIDEO when ACPI is enabled
         # but for select to work, need to select ACPI_VIDEO's 
dependencies, ick
-       select BACKLIGHT_CLASS_DEVICE if ACPI
         select INPUT if ACPI
         select X86_PLATFORM_DEVICES if ACPI
         select ACPI_WMI if ACPI

I get:
drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on 
BACKLIGHT_CLASS_DEVICE
drivers/video/backlight/Kconfig:143:    symbol BACKLIGHT_CLASS_DEVICE is 
selected by DRM_FSL_DCU
drivers/gpu/drm/fsl-dcu/Kconfig:2:      symbol DRM_FSL_DCU depends on 
COMMON_CLK
drivers/clk/Kconfig:21: symbol COMMON_CLK is selected by X86_INTEL_QUARK
arch/x86/Kconfig:633:   symbol X86_INTEL_QUARK depends on 
X86_PLATFORM_DEVICES
drivers/platform/x86/Kconfig:6: symbol X86_PLATFORM_DEVICES is selected 
by DRM_I915


Those dependencies are really cumbersome :/.

> Documentation/kbuild/kconfig-language.rst:
> 
>    Note:
> 	select should be used with care. select will force
> 	a symbol to a value without visiting the dependencies.
> 	By abusing select you are able to select a symbol FOO even
> 	if FOO depends on BAR that is not set.
> 	In general use select only for non-visible symbols
> 	(no prompts anywhere) and for symbols with no dependencies.
> 	That will limit the usefulness but on the other hand avoid
> 	the illegal configurations all over.
> 
> 
> BR,
> Jani.
> 
>>
>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
>> Cc: David Airlie <airlied@gmail.com>
>> Cc: Daniel Vetter <daniel@ffwll.ch>
>> Cc: intel-gfx@lists.freedesktop.org
>> Cc: dri-devel@lists.freedesktop.org
>> Reported-by: Martin Liška <mliska@suse.cz>
>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
>> ---
>>   drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>>   drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
>> index beba39a38c87..c1ba68796b6d 100644
>> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
>> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>>   	mutex_unlock(&dev_priv->display.backlight.lock);
>>   }
>>   
>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>   static u32 intel_panel_get_backlight(struct intel_connector *connector)
>>   {
>>   	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
>> index 339643f63897..207fe1c613d8 100644
>> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
>> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>>   u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>>   u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>>   
>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>   int intel_backlight_device_register(struct intel_connector *connector);
>>   void intel_backlight_device_unregister(struct intel_connector *connector);
>>   #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
> 

-- 
js
suse labs

Re: [PATCH 1/2] drm/i915/display: fix randconfig build

[Jiri Slaby]

On 04. 10. 22, 12:52, Jani Nikula wrote:
> On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
>> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
>> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>>
>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
>> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>>
>> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
>> with the above config, backlight support is disabled.
> 
> So I don't want this. I'll take a patch that fixes the dependencies to
> block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
> and IMO using IS_REACHABLE() is a workaround to hide a broken config
> under the carpet.
> 
> The right thing to do is
> 
> config DRM_I915
> 	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.
> 
> We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
> too, and a combo of selecting and depending leads to circular
> dependencies. But depending is the right fix.

I'm not sure what should I do now. If I do:
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -4,6 +4,7 @@ config DRM_I915
         depends on DRM
         depends on X86 && PCI
         depends on !PREEMPT_RT
+       depends on (BACKLIGHT_CLASS_DEVICE && ACPI) || 
(BACKLIGHT_CLASS_DEVICE=n && ACPI=n)
         select INTEL_GTT if X86
         select INTERVAL_TREE
         # we need shmfs for the swappable backing store, and in particular
@@ -21,7 +22,6 @@ config DRM_I915
         select IRQ_WORK
         # i915 depends on ACPI_VIDEO when ACPI is enabled
         # but for select to work, need to select ACPI_VIDEO's 
dependencies, ick
-       select BACKLIGHT_CLASS_DEVICE if ACPI
         select INPUT if ACPI
         select X86_PLATFORM_DEVICES if ACPI
         select ACPI_WMI if ACPI

I get:
drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on 
BACKLIGHT_CLASS_DEVICE
drivers/video/backlight/Kconfig:143:    symbol BACKLIGHT_CLASS_DEVICE is 
selected by DRM_FSL_DCU
drivers/gpu/drm/fsl-dcu/Kconfig:2:      symbol DRM_FSL_DCU depends on 
COMMON_CLK
drivers/clk/Kconfig:21: symbol COMMON_CLK is selected by X86_INTEL_QUARK
arch/x86/Kconfig:633:   symbol X86_INTEL_QUARK depends on 
X86_PLATFORM_DEVICES
drivers/platform/x86/Kconfig:6: symbol X86_PLATFORM_DEVICES is selected 
by DRM_I915


Those dependencies are really cumbersome :/.

> Documentation/kbuild/kconfig-language.rst:
> 
>    Note:
> 	select should be used with care. select will force
> 	a symbol to a value without visiting the dependencies.
> 	By abusing select you are able to select a symbol FOO even
> 	if FOO depends on BAR that is not set.
> 	In general use select only for non-visible symbols
> 	(no prompts anywhere) and for symbols with no dependencies.
> 	That will limit the usefulness but on the other hand avoid
> 	the illegal configurations all over.
> 
> 
> BR,
> Jani.
> 
>>
>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
>> Cc: David Airlie <airlied@gmail.com>
>> Cc: Daniel Vetter <daniel@ffwll.ch>
>> Cc: intel-gfx@lists.freedesktop.org
>> Cc: dri-devel@lists.freedesktop.org
>> Reported-by: Martin Liška <mliska@suse.cz>
>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
>> ---
>>   drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>>   drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
>> index beba39a38c87..c1ba68796b6d 100644
>> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
>> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>>   	mutex_unlock(&dev_priv->display.backlight.lock);
>>   }
>>   
>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>   static u32 intel_panel_get_backlight(struct intel_connector *connector)
>>   {
>>   	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
>> index 339643f63897..207fe1c613d8 100644
>> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
>> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>>   u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>>   u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>>   
>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>   int intel_backlight_device_register(struct intel_connector *connector);
>>   void intel_backlight_device_unregister(struct intel_connector *connector);
>>   #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
> 

-- 
js
suse labs

Re: [Intel-gfx] [PATCH 1/2] drm/i915/display: fix randconfig build

[Jiri Slaby]

On 04. 10. 22, 12:52, Jani Nikula wrote:
> On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
>> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
>> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>>
>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
>> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>>
>> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
>> with the above config, backlight support is disabled.
> 
> So I don't want this. I'll take a patch that fixes the dependencies to
> block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
> and IMO using IS_REACHABLE() is a workaround to hide a broken config
> under the carpet.
> 
> The right thing to do is
> 
> config DRM_I915
> 	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.
> 
> We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
> too, and a combo of selecting and depending leads to circular
> dependencies. But depending is the right fix.

I'm not sure what should I do now. If I do:
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -4,6 +4,7 @@ config DRM_I915
         depends on DRM
         depends on X86 && PCI
         depends on !PREEMPT_RT
+       depends on (BACKLIGHT_CLASS_DEVICE && ACPI) || 
(BACKLIGHT_CLASS_DEVICE=n && ACPI=n)
         select INTEL_GTT if X86
         select INTERVAL_TREE
         # we need shmfs for the swappable backing store, and in particular
@@ -21,7 +22,6 @@ config DRM_I915
         select IRQ_WORK
         # i915 depends on ACPI_VIDEO when ACPI is enabled
         # but for select to work, need to select ACPI_VIDEO's 
dependencies, ick
-       select BACKLIGHT_CLASS_DEVICE if ACPI
         select INPUT if ACPI
         select X86_PLATFORM_DEVICES if ACPI
         select ACPI_WMI if ACPI

I get:
drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on 
BACKLIGHT_CLASS_DEVICE
drivers/video/backlight/Kconfig:143:    symbol BACKLIGHT_CLASS_DEVICE is 
selected by DRM_FSL_DCU
drivers/gpu/drm/fsl-dcu/Kconfig:2:      symbol DRM_FSL_DCU depends on 
COMMON_CLK
drivers/clk/Kconfig:21: symbol COMMON_CLK is selected by X86_INTEL_QUARK
arch/x86/Kconfig:633:   symbol X86_INTEL_QUARK depends on 
X86_PLATFORM_DEVICES
drivers/platform/x86/Kconfig:6: symbol X86_PLATFORM_DEVICES is selected 
by DRM_I915


Those dependencies are really cumbersome :/.

> Documentation/kbuild/kconfig-language.rst:
> 
>    Note:
> 	select should be used with care. select will force
> 	a symbol to a value without visiting the dependencies.
> 	By abusing select you are able to select a symbol FOO even
> 	if FOO depends on BAR that is not set.
> 	In general use select only for non-visible symbols
> 	(no prompts anywhere) and for symbols with no dependencies.
> 	That will limit the usefulness but on the other hand avoid
> 	the illegal configurations all over.
> 
> 
> BR,
> Jani.
> 
>>
>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
>> Cc: David Airlie <airlied@gmail.com>
>> Cc: Daniel Vetter <daniel@ffwll.ch>
>> Cc: intel-gfx@lists.freedesktop.org
>> Cc: dri-devel@lists.freedesktop.org
>> Reported-by: Martin Liška <mliska@suse.cz>
>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
>> ---
>>   drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>>   drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
>> index beba39a38c87..c1ba68796b6d 100644
>> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
>> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>>   	mutex_unlock(&dev_priv->display.backlight.lock);
>>   }
>>   
>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>   static u32 intel_panel_get_backlight(struct intel_connector *connector)
>>   {
>>   	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
>> index 339643f63897..207fe1c613d8 100644
>> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
>> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>>   u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>>   u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>>   
>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>   int intel_backlight_device_register(struct intel_connector *connector);
>>   void intel_backlight_device_unregister(struct intel_connector *connector);
>>   #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
> 

-- 
js
suse labs

Re: [PATCH 1/2] drm/i915/display: fix randconfig build

[Jani Nikula]

On Wed, 05 Oct 2022, Jiri Slaby <jirislaby@kernel.org> wrote:
> On 04. 10. 22, 12:52, Jani Nikula wrote:
>> On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
>>> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
>>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
>>> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>>>
>>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
>>> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>>>
>>> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
>>> with the above config, backlight support is disabled.
>> 
>> So I don't want this. I'll take a patch that fixes the dependencies to
>> block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
>> and IMO using IS_REACHABLE() is a workaround to hide a broken config
>> under the carpet.
>> 
>> The right thing to do is
>> 
>> config DRM_I915
>> 	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.
>> 
>> We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
>> too, and a combo of selecting and depending leads to circular
>> dependencies. But depending is the right fix.
>
> I'm not sure what should I do now. If I do:
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -4,6 +4,7 @@ config DRM_I915
>          depends on DRM
>          depends on X86 && PCI
>          depends on !PREEMPT_RT
> +       depends on (BACKLIGHT_CLASS_DEVICE && ACPI) || 
> (BACKLIGHT_CLASS_DEVICE=n && ACPI=n)
>          select INTEL_GTT if X86
>          select INTERVAL_TREE
>          # we need shmfs for the swappable backing store, and in particular
> @@ -21,7 +22,6 @@ config DRM_I915
>          select IRQ_WORK
>          # i915 depends on ACPI_VIDEO when ACPI is enabled
>          # but for select to work, need to select ACPI_VIDEO's 
> dependencies, ick
> -       select BACKLIGHT_CLASS_DEVICE if ACPI
>          select INPUT if ACPI
>          select X86_PLATFORM_DEVICES if ACPI
>          select ACPI_WMI if ACPI
>
> I get:
> drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
> drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on 
> BACKLIGHT_CLASS_DEVICE
> drivers/video/backlight/Kconfig:143:    symbol BACKLIGHT_CLASS_DEVICE is 
> selected by DRM_FSL_DCU
> drivers/gpu/drm/fsl-dcu/Kconfig:2:      symbol DRM_FSL_DCU depends on 
> COMMON_CLK
> drivers/clk/Kconfig:21: symbol COMMON_CLK is selected by X86_INTEL_QUARK
> arch/x86/Kconfig:633:   symbol X86_INTEL_QUARK depends on 
> X86_PLATFORM_DEVICES
> drivers/platform/x86/Kconfig:6: symbol X86_PLATFORM_DEVICES is selected 
> by DRM_I915
>
>
> Those dependencies are really cumbersome :/.

Yes. They could be fixed, though [1]. IS_REACHABLE() is just band-aid.

BR,
Jani.


[1] https://lore.kernel.org/r/1413580403-16225-1-git-send-email-jani.nikula@intel.com

>
>> Documentation/kbuild/kconfig-language.rst:
>> 
>>    Note:
>> 	select should be used with care. select will force
>> 	a symbol to a value without visiting the dependencies.
>> 	By abusing select you are able to select a symbol FOO even
>> 	if FOO depends on BAR that is not set.
>> 	In general use select only for non-visible symbols
>> 	(no prompts anywhere) and for symbols with no dependencies.
>> 	That will limit the usefulness but on the other hand avoid
>> 	the illegal configurations all over.
>> 
>> 
>> BR,
>> Jani.
>> 
>>>
>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>>> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
>>> Cc: David Airlie <airlied@gmail.com>
>>> Cc: Daniel Vetter <daniel@ffwll.ch>
>>> Cc: intel-gfx@lists.freedesktop.org
>>> Cc: dri-devel@lists.freedesktop.org
>>> Reported-by: Martin Liška <mliska@suse.cz>
>>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
>>> ---
>>>   drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>>>   drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
>>> index beba39a38c87..c1ba68796b6d 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
>>> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>>>   	mutex_unlock(&dev_priv->display.backlight.lock);
>>>   }
>>>   
>>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>>   static u32 intel_panel_get_backlight(struct intel_connector *connector)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
>>> index 339643f63897..207fe1c613d8 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
>>> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>>>   u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>>>   u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>>>   
>>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>>   int intel_backlight_device_register(struct intel_connector *connector);
>>>   void intel_backlight_device_unregister(struct intel_connector *connector);
>>>   #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
>> 

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [PATCH 1/2] drm/i915/display: fix randconfig build

[Jani Nikula]

On Wed, 05 Oct 2022, Jiri Slaby <jirislaby@kernel.org> wrote:
> On 04. 10. 22, 12:52, Jani Nikula wrote:
>> On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
>>> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
>>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
>>> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>>>
>>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
>>> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>>>
>>> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
>>> with the above config, backlight support is disabled.
>> 
>> So I don't want this. I'll take a patch that fixes the dependencies to
>> block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
>> and IMO using IS_REACHABLE() is a workaround to hide a broken config
>> under the carpet.
>> 
>> The right thing to do is
>> 
>> config DRM_I915
>> 	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.
>> 
>> We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
>> too, and a combo of selecting and depending leads to circular
>> dependencies. But depending is the right fix.
>
> I'm not sure what should I do now. If I do:
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -4,6 +4,7 @@ config DRM_I915
>          depends on DRM
>          depends on X86 && PCI
>          depends on !PREEMPT_RT
> +       depends on (BACKLIGHT_CLASS_DEVICE && ACPI) || 
> (BACKLIGHT_CLASS_DEVICE=n && ACPI=n)
>          select INTEL_GTT if X86
>          select INTERVAL_TREE
>          # we need shmfs for the swappable backing store, and in particular
> @@ -21,7 +22,6 @@ config DRM_I915
>          select IRQ_WORK
>          # i915 depends on ACPI_VIDEO when ACPI is enabled
>          # but for select to work, need to select ACPI_VIDEO's 
> dependencies, ick
> -       select BACKLIGHT_CLASS_DEVICE if ACPI
>          select INPUT if ACPI
>          select X86_PLATFORM_DEVICES if ACPI
>          select ACPI_WMI if ACPI
>
> I get:
> drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
> drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on 
> BACKLIGHT_CLASS_DEVICE
> drivers/video/backlight/Kconfig:143:    symbol BACKLIGHT_CLASS_DEVICE is 
> selected by DRM_FSL_DCU
> drivers/gpu/drm/fsl-dcu/Kconfig:2:      symbol DRM_FSL_DCU depends on 
> COMMON_CLK
> drivers/clk/Kconfig:21: symbol COMMON_CLK is selected by X86_INTEL_QUARK
> arch/x86/Kconfig:633:   symbol X86_INTEL_QUARK depends on 
> X86_PLATFORM_DEVICES
> drivers/platform/x86/Kconfig:6: symbol X86_PLATFORM_DEVICES is selected 
> by DRM_I915
>
>
> Those dependencies are really cumbersome :/.

Yes. They could be fixed, though [1]. IS_REACHABLE() is just band-aid.

BR,
Jani.


[1] https://lore.kernel.org/r/1413580403-16225-1-git-send-email-jani.nikula@intel.com

>
>> Documentation/kbuild/kconfig-language.rst:
>> 
>>    Note:
>> 	select should be used with care. select will force
>> 	a symbol to a value without visiting the dependencies.
>> 	By abusing select you are able to select a symbol FOO even
>> 	if FOO depends on BAR that is not set.
>> 	In general use select only for non-visible symbols
>> 	(no prompts anywhere) and for symbols with no dependencies.
>> 	That will limit the usefulness but on the other hand avoid
>> 	the illegal configurations all over.
>> 
>> 
>> BR,
>> Jani.
>> 
>>>
>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>>> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
>>> Cc: David Airlie <airlied@gmail.com>
>>> Cc: Daniel Vetter <daniel@ffwll.ch>
>>> Cc: intel-gfx@lists.freedesktop.org
>>> Cc: dri-devel@lists.freedesktop.org
>>> Reported-by: Martin Liška <mliska@suse.cz>
>>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
>>> ---
>>>   drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>>>   drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
>>> index beba39a38c87..c1ba68796b6d 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
>>> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>>>   	mutex_unlock(&dev_priv->display.backlight.lock);
>>>   }
>>>   
>>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>>   static u32 intel_panel_get_backlight(struct intel_connector *connector)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
>>> index 339643f63897..207fe1c613d8 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
>>> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>>>   u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>>>   u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>>>   
>>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>>   int intel_backlight_device_register(struct intel_connector *connector);
>>>   void intel_backlight_device_unregister(struct intel_connector *connector);
>>>   #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
>> 

-- 
Jani Nikula, Intel Open Source Graphics Center

Re: [Intel-gfx] [PATCH 1/2] drm/i915/display: fix randconfig build

[Jani Nikula]

On Wed, 05 Oct 2022, Jiri Slaby <jirislaby@kernel.org> wrote:
> On 04. 10. 22, 12:52, Jani Nikula wrote:
>> On Tue, 04 Oct 2022, "Jiri Slaby (SUSE)" <jirislaby@kernel.org> wrote:
>>> When DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m, the build fails:
>>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_register':
>>> intel_backlight.c:(.text+0x5587): undefined reference to `backlight_device_get_by_name'
>>>
>>> ld: drivers/gpu/drm/i915/display/intel_backlight.o: in function `intel_backlight_device_unregister':
>>> intel_backlight.c:(.text+0x576e): undefined reference to `backlight_device_unregister'
>>>
>>> To fix this, use IS_REACHABLE(), not IS_ENABLED() in backlight. That is,
>>> with the above config, backlight support is disabled.
>> 
>> So I don't want this. I'll take a patch that fixes the dependencies to
>> block DRM_I915=y and BACKLIGHT_CLASS_DEVICE=m. Nobody wants that combo,
>> and IMO using IS_REACHABLE() is a workaround to hide a broken config
>> under the carpet.
>> 
>> The right thing to do is
>> 
>> config DRM_I915
>> 	depends on BACKLIGHT_CLASS_DEVICE || BACKLIGHT_CLASS_DEVICE=n.
>> 
>> We're selecting BACKLIGHT_CLASS_DEVICE because almost everyone else is
>> too, and a combo of selecting and depending leads to circular
>> dependencies. But depending is the right fix.
>
> I'm not sure what should I do now. If I do:
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -4,6 +4,7 @@ config DRM_I915
>          depends on DRM
>          depends on X86 && PCI
>          depends on !PREEMPT_RT
> +       depends on (BACKLIGHT_CLASS_DEVICE && ACPI) || 
> (BACKLIGHT_CLASS_DEVICE=n && ACPI=n)
>          select INTEL_GTT if X86
>          select INTERVAL_TREE
>          # we need shmfs for the swappable backing store, and in particular
> @@ -21,7 +22,6 @@ config DRM_I915
>          select IRQ_WORK
>          # i915 depends on ACPI_VIDEO when ACPI is enabled
>          # but for select to work, need to select ACPI_VIDEO's 
> dependencies, ick
> -       select BACKLIGHT_CLASS_DEVICE if ACPI
>          select INPUT if ACPI
>          select X86_PLATFORM_DEVICES if ACPI
>          select ACPI_WMI if ACPI
>
> I get:
> drivers/gpu/drm/i915/Kconfig:2:error: recursive dependency detected!
> drivers/gpu/drm/i915/Kconfig:2: symbol DRM_I915 depends on 
> BACKLIGHT_CLASS_DEVICE
> drivers/video/backlight/Kconfig:143:    symbol BACKLIGHT_CLASS_DEVICE is 
> selected by DRM_FSL_DCU
> drivers/gpu/drm/fsl-dcu/Kconfig:2:      symbol DRM_FSL_DCU depends on 
> COMMON_CLK
> drivers/clk/Kconfig:21: symbol COMMON_CLK is selected by X86_INTEL_QUARK
> arch/x86/Kconfig:633:   symbol X86_INTEL_QUARK depends on 
> X86_PLATFORM_DEVICES
> drivers/platform/x86/Kconfig:6: symbol X86_PLATFORM_DEVICES is selected 
> by DRM_I915
>
>
> Those dependencies are really cumbersome :/.

Yes. They could be fixed, though [1]. IS_REACHABLE() is just band-aid.

BR,
Jani.


[1] https://lore.kernel.org/r/1413580403-16225-1-git-send-email-jani.nikula@intel.com

>
>> Documentation/kbuild/kconfig-language.rst:
>> 
>>    Note:
>> 	select should be used with care. select will force
>> 	a symbol to a value without visiting the dependencies.
>> 	By abusing select you are able to select a symbol FOO even
>> 	if FOO depends on BAR that is not set.
>> 	In general use select only for non-visible symbols
>> 	(no prompts anywhere) and for symbols with no dependencies.
>> 	That will limit the usefulness but on the other hand avoid
>> 	the illegal configurations all over.
>> 
>> 
>> BR,
>> Jani.
>> 
>>>
>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>>> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
>>> Cc: David Airlie <airlied@gmail.com>
>>> Cc: Daniel Vetter <daniel@ffwll.ch>
>>> Cc: intel-gfx@lists.freedesktop.org
>>> Cc: dri-devel@lists.freedesktop.org
>>> Reported-by: Martin Liška <mliska@suse.cz>
>>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
>>> ---
>>>   drivers/gpu/drm/i915/display/intel_backlight.c | 2 +-
>>>   drivers/gpu/drm/i915/display/intel_backlight.h | 2 +-
>>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
>>> index beba39a38c87..c1ba68796b6d 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
>>> @@ -825,7 +825,7 @@ void intel_backlight_enable(const struct intel_crtc_state *crtc_state,
>>>   	mutex_unlock(&dev_priv->display.backlight.lock);
>>>   }
>>>   
>>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>>   static u32 intel_panel_get_backlight(struct intel_connector *connector)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>>> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
>>> index 339643f63897..207fe1c613d8 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_backlight.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_backlight.h
>>> @@ -36,7 +36,7 @@ u32 intel_backlight_invert_pwm_level(struct intel_connector *connector, u32 leve
>>>   u32 intel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
>>>   u32 intel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
>>>   
>>> -#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>> +#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
>>>   int intel_backlight_device_register(struct intel_connector *connector);
>>>   void intel_backlight_device_unregister(struct intel_connector *connector);
>>>   #else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
>> 

-- 
Jani Nikula, Intel Open Source Graphics Center

[Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with [1/2] drm/i915/display: fix randconfig build (rev2)

[Patchwork]

== Series Details ==

Series: series starting with [1/2] drm/i915/display: fix randconfig build (rev2)
URL   : https://patchwork.freedesktop.org/series/109542/
State : failure

== Summary ==

Error: patch https://patchwork.freedesktop.org/api/1.0/series/109542/revisions/2/mbox/ not applied
Applying: drm/i915/display: fix randconfig build
error: corrupt patch at line 8
error: could not build fake ancestor
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 drm/i915/display: fix randconfig build
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".