[PATCH v3 0/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[PATCH v3 0/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[Javier Martinez Canillas]

Hello,

This series contain patches suggested by Thomas Zimmermann as a feedback for
"[RFC PATCH v4 00/11] Fix some race between sysfb device registration and
drivers probe" [0].

Since other changes in [0] were more controversial, I decided to just split
this part in a new patch-set and revisit the rest of the patches later.

This is a v2 that addresses issues pointed out in v1.

Patch #1 is just a cleanup since when working on this noticed that some DRM
drivers were passing as preferred bits per pixel to drm_fbdev_generic_setup()
the value that is the default anyways.

Patch #2 renames the 'preferred_bpp' drm_fbdev_generic_setup() parameter to
'options', and make this a multi field parameter so that it can be extended
later to pass other options as well.

Patch #3 finally adds the new DRM_FB_FW option and makes simpledrm to use it
so that the registered framebuffer device is also marked as firmware provided.

The patches were tested on a rpi4 board with the vc4 DRM driver built as a
module and either simplefb or simpledrm built-in.

[0]: https://lore.kernel.org/lkml/20220429084253.1085911-1-javierm@redhat.com/

Changes in v3:
- Drop the preferred_bpp local variable (Laurent Pinchart).
- Add a const qualifier to options parameter (Laurent Pinchart).
- Drop the firmware local variable (Laurent Pinchart).
- Use DRM_FB_OPTION() since DRM_FB_SET_OPTION() got renamed (kernel test robot).

Changes in v2:
- Rename DRM_FB_SET_OPTION() to DRM_FB_OPTION() and make more clear in
  the kernel-doc what this macro does (Laurent Pinchart).
- Fix some kernel-doc issues I didn't notice in v1.
- Add Reviewed-by tags from Thomas and Laurent.

Javier Martinez Canillas (3):
  drm: Remove superfluous arg when calling to drm_fbdev_generic_setup()
  drm/fb-helper: Rename preferred_bpp drm_fbdev_generic_setup()
    parameter
  drm: Allow simpledrm to setup its emulated FB as firmware provided

 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |  6 ++--
 drivers/gpu/drm/arm/hdlcd_drv.c               |  2 +-
 drivers/gpu/drm/arm/malidp_drv.c              |  2 +-
 drivers/gpu/drm/aspeed/aspeed_gfx_drv.c       |  2 +-
 drivers/gpu/drm/ast/ast_drv.c                 |  2 +-
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c  |  2 +-
 drivers/gpu/drm/drm_drv.c                     |  2 +-
 drivers/gpu/drm/drm_fb_helper.c               | 34 ++++++++++++++-----
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c     |  2 +-
 .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c   |  2 +-
 .../gpu/drm/hisilicon/kirin/kirin_drm_drv.c   |  2 +-
 drivers/gpu/drm/imx/dcss/dcss-kms.c           |  2 +-
 drivers/gpu/drm/imx/imx-drm-core.c            |  2 +-
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c     |  2 +-
 drivers/gpu/drm/mcde/mcde_drv.c               |  2 +-
 drivers/gpu/drm/mediatek/mtk_drm_drv.c        |  2 +-
 drivers/gpu/drm/meson/meson_drv.c             |  2 +-
 drivers/gpu/drm/mxsfb/mxsfb_drv.c             |  2 +-
 drivers/gpu/drm/pl111/pl111_drv.c             |  2 +-
 drivers/gpu/drm/qxl/qxl_drv.c                 |  2 +-
 drivers/gpu/drm/rcar-du/rcar_du_drv.c         |  2 +-
 drivers/gpu/drm/sti/sti_drv.c                 |  2 +-
 drivers/gpu/drm/stm/drv.c                     |  2 +-
 drivers/gpu/drm/sun4i/sun4i_drv.c             |  2 +-
 drivers/gpu/drm/tidss/tidss_drv.c             |  2 +-
 drivers/gpu/drm/tilcdc/tilcdc_drv.c           |  2 +-
 drivers/gpu/drm/tiny/arcpgu.c                 |  2 +-
 drivers/gpu/drm/tiny/bochs.c                  |  2 +-
 drivers/gpu/drm/tiny/cirrus.c                 |  2 +-
 drivers/gpu/drm/tiny/simpledrm.c              |  2 +-
 drivers/gpu/drm/tve200/tve200_drv.c           |  2 +-
 drivers/gpu/drm/vboxvideo/vbox_drv.c          |  2 +-
 drivers/gpu/drm/vc4/vc4_drv.c                 |  2 +-
 drivers/gpu/drm/virtio/virtgpu_drv.c          |  2 +-
 drivers/gpu/drm/xlnx/zynqmp_dpsub.c           |  2 +-
 include/drm/drm_fb_helper.h                   | 24 ++++++++++++-
 36 files changed, 85 insertions(+), 45 deletions(-)

-- 
2.35.1

[PATCH v3 1/3] drm: Remove superfluous arg when calling to drm_fbdev_generic_setup()

[Javier Martinez Canillas]

The drm_fbdev_generic_setup() function already sets the preferred bits per
pixel for the device to dev->mode_config.preferred_depth, if preferred_bpp
value is zero.

Passing the same value to the function is unnecessary. Let's cleanup that
in the two drivers that do it.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---

(no changes since v1)

 drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 2 +-
 drivers/gpu/drm/tiny/cirrus.c                   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index fe4269c5aa0a..ace92459e462 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -349,7 +349,7 @@ static int hibmc_pci_probe(struct pci_dev *pdev,
 		goto err_unload;
 	}
 
-	drm_fbdev_generic_setup(dev, dev->mode_config.preferred_depth);
+	drm_fbdev_generic_setup(dev, 0);
 
 	return 0;
 
diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index c8e791840862..ed5a2e14894a 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c
@@ -601,7 +601,7 @@ static int cirrus_pci_probe(struct pci_dev *pdev,
 	if (ret)
 		return ret;
 
-	drm_fbdev_generic_setup(dev, dev->mode_config.preferred_depth);
+	drm_fbdev_generic_setup(dev, 0);
 	return 0;
 }
 
-- 
2.35.1

[PATCH v3 2/3] drm/fb-helper: Rename preferred_bpp drm_fbdev_generic_setup() parameter

[Javier Martinez Canillas]

By default the bits per pixel for the emulated framebuffer device is set
to dev->mode_config.preferred_depth, but some devices need another value.

Since this second parameter is only used by a few drivers, and to allow
drivers to use it for passing other configurations when registering the
fbdev, rename @preferred_bpp to @options and make it a multi-field param.

The DRM_FB_OPTION() and DRM_FB_GET_OPTION() macros are provided to drivers
for computing options bitfield values and getting the values respectively

For now, only the DRM_FB_BPP option exists but other options can be added.

Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---

Changes in v3:
- Drop the preferred_bpp local variable (Laurent Pinchart).
- Add a const qualifier to options parameter (Laurent Pinchart).

Changes in v2:
- Rename DRM_FB_SET_OPTION() to DRM_FB_OPTION() and make more clear in
  the kernel-doc what this macro does (Laurent Pinchart).
- Fix some kernel-doc issues I didn't notice in v1.
- Add Reviewed-by tags from Thomas and Laurent.

 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |  6 +++--
 drivers/gpu/drm/arm/hdlcd_drv.c               |  2 +-
 drivers/gpu/drm/arm/malidp_drv.c              |  2 +-
 drivers/gpu/drm/aspeed/aspeed_gfx_drv.c       |  2 +-
 drivers/gpu/drm/ast/ast_drv.c                 |  2 +-
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c  |  2 +-
 drivers/gpu/drm/drm_drv.c                     |  2 +-
 drivers/gpu/drm/drm_fb_helper.c               | 26 ++++++++++++-------
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c     |  2 +-
 .../gpu/drm/hisilicon/kirin/kirin_drm_drv.c   |  2 +-
 drivers/gpu/drm/imx/dcss/dcss-kms.c           |  2 +-
 drivers/gpu/drm/imx/imx-drm-core.c            |  2 +-
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c     |  2 +-
 drivers/gpu/drm/mcde/mcde_drv.c               |  2 +-
 drivers/gpu/drm/mediatek/mtk_drm_drv.c        |  2 +-
 drivers/gpu/drm/meson/meson_drv.c             |  2 +-
 drivers/gpu/drm/mxsfb/mxsfb_drv.c             |  2 +-
 drivers/gpu/drm/pl111/pl111_drv.c             |  2 +-
 drivers/gpu/drm/qxl/qxl_drv.c                 |  2 +-
 drivers/gpu/drm/rcar-du/rcar_du_drv.c         |  2 +-
 drivers/gpu/drm/sti/sti_drv.c                 |  2 +-
 drivers/gpu/drm/stm/drv.c                     |  2 +-
 drivers/gpu/drm/sun4i/sun4i_drv.c             |  2 +-
 drivers/gpu/drm/tidss/tidss_drv.c             |  2 +-
 drivers/gpu/drm/tilcdc/tilcdc_drv.c           |  2 +-
 drivers/gpu/drm/tiny/arcpgu.c                 |  2 +-
 drivers/gpu/drm/tiny/bochs.c                  |  2 +-
 drivers/gpu/drm/tve200/tve200_drv.c           |  2 +-
 drivers/gpu/drm/vboxvideo/vbox_drv.c          |  2 +-
 drivers/gpu/drm/vc4/vc4_drv.c                 |  2 +-
 drivers/gpu/drm/virtio/virtgpu_drv.c          |  2 +-
 drivers/gpu/drm/xlnx/zynqmp_dpsub.c           |  2 +-
 include/drm/drm_fb_helper.h                   | 14 +++++++++-
 33 files changed, 64 insertions(+), 42 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index b03663f42cc9..0c54470975e3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2118,9 +2118,11 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
 	    !list_empty(&adev_to_drm(adev)->mode_config.connector_list)) {
 		/* select 8 bpp console on low vram cards */
 		if (adev->gmc.real_vram_size <= (32*1024*1024))
-			drm_fbdev_generic_setup(adev_to_drm(adev), 8);
+			drm_fbdev_generic_setup(adev_to_drm(adev),
+						DRM_FB_OPTION(DRM_FB_BPP, 8));
 		else
-			drm_fbdev_generic_setup(adev_to_drm(adev), 32);
+			drm_fbdev_generic_setup(adev_to_drm(adev),
+						DRM_FB_OPTION(DRM_FB_BPP, 32));
 	}
 
 	ret = amdgpu_debugfs_init(adev);
diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
index e89ae0ec60eb..b69b1e5be379 100644
--- a/drivers/gpu/drm/arm/hdlcd_drv.c
+++ b/drivers/gpu/drm/arm/hdlcd_drv.c
@@ -321,7 +321,7 @@ static int hdlcd_drm_bind(struct device *dev)
 	if (ret)
 		goto err_register;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index d5aef21426cf..25685b579a05 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -863,7 +863,7 @@ static int malidp_bind(struct device *dev)
 	if (ret)
 		goto register_fail;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
index 7780b72de9e8..dcccc2e93aea 100644
--- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
+++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
@@ -343,7 +343,7 @@ static int aspeed_gfx_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_unload;
 
-	drm_fbdev_generic_setup(&priv->drm, 32);
+	drm_fbdev_generic_setup(&priv->drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 	return 0;
 
 err_unload:
diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 7465c4f0156a..115be73e9b02 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -126,7 +126,7 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (ret)
 		return ret;
 
-	drm_fbdev_generic_setup(dev, 32);
+	drm_fbdev_generic_setup(dev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
index 651e3c109360..d2ced1a03df9 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
@@ -760,7 +760,7 @@ static int atmel_hlcdc_dc_drm_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_unload;
 
-	drm_fbdev_generic_setup(ddev, 24);
+	drm_fbdev_generic_setup(ddev, DRM_FB_OPTION(DRM_FB_BPP, 24));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 8214a0b1ab7f..9fbc2287c876 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -324,7 +324,7 @@ void drm_minor_release(struct drm_minor *minor)
  *		if (ret)
  *			return ret;
  *
- *		drm_fbdev_generic_setup(drm, 32);
+ *		drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
  *
  *		return 0;
  *	}
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index d265a73313c9..52042ba1e4cf 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2501,8 +2501,17 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = {
 /**
  * drm_fbdev_generic_setup() - Setup generic fbdev emulation
  * @dev: DRM device
- * @preferred_bpp: Preferred bits per pixel for the device.
- *                 @dev->mode_config.preferred_depth is used if this is zero.
+ * @options: options for the registered framebuffer.
+ *
+ * The @options parameter is a multi-field parameter that can contain
+ * different options for the emulated framebuffer device registered.
+ *
+ * The options field values can be set using DRM_FB_OPTION() to compute
+ * the value according to the option bitfield and can be obtained using
+ * DRM_FB_GET_OPTION(). The options fields are the following:
+ *
+ * * DRM_FB_BPP: bits per pixel for the device. If the field is not set,
+ *   @dev->mode_config.preferred_depth is used instead.
  *
  * This function sets up generic fbdev emulation for drivers that supports
  * dumb buffers with a virtual address and that can be mmap'ed.
@@ -2525,8 +2534,7 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = {
  *
  * The fbdev is destroyed by drm_dev_unregister().
  */
-void drm_fbdev_generic_setup(struct drm_device *dev,
-			     unsigned int preferred_bpp)
+void drm_fbdev_generic_setup(struct drm_device *dev, const unsigned int options)
 {
 	struct drm_fb_helper *fb_helper;
 	int ret;
@@ -2555,11 +2563,11 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
 	 * mess, resulting in some drivers picking wrong fbdev defaults and
 	 * others wrong preferred_depth defaults.
 	 */
-	if (!preferred_bpp)
-		preferred_bpp = dev->mode_config.preferred_depth;
-	if (!preferred_bpp)
-		preferred_bpp = 32;
-	fb_helper->preferred_bpp = preferred_bpp;
+	fb_helper->preferred_bpp = DRM_FB_GET_OPTION(DRM_FB_BPP, options);
+	if (!fb_helper->preferred_bpp)
+		fb_helper->preferred_bpp = dev->mode_config.preferred_depth;
+	if (!fb_helper->preferred_bpp)
+		fb_helper->preferred_bpp = 32;
 
 	ret = drm_fbdev_client_hotplug(&fb_helper->client);
 	if (ret)
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 7a503bf08d0f..293390f0d99c 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -334,7 +334,7 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto put;
 
-	drm_fbdev_generic_setup(drm, legacyfb_depth);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, legacyfb_depth));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
index 2af51df6dca7..eb6f3e5d4c95 100644
--- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c
@@ -237,7 +237,7 @@ static int kirin_drm_bind(struct device *dev)
 	if (ret)
 		goto err_kms_cleanup;
 
-	drm_fbdev_generic_setup(drm_dev, 32);
+	drm_fbdev_generic_setup(drm_dev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/imx/dcss/dcss-kms.c b/drivers/gpu/drm/imx/dcss/dcss-kms.c
index 9b84df34a6a1..f84b54793d96 100644
--- a/drivers/gpu/drm/imx/dcss/dcss-kms.c
+++ b/drivers/gpu/drm/imx/dcss/dcss-kms.c
@@ -148,7 +148,7 @@ struct dcss_kms_dev *dcss_kms_attach(struct dcss_dev *dcss)
 	if (ret)
 		goto cleanup_crtc;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return kms;
 
diff --git a/drivers/gpu/drm/imx/imx-drm-core.c b/drivers/gpu/drm/imx/imx-drm-core.c
index a57812ec36b1..5fd8cf003a4c 100644
--- a/drivers/gpu/drm/imx/imx-drm-core.c
+++ b/drivers/gpu/drm/imx/imx-drm-core.c
@@ -251,7 +251,7 @@ static int imx_drm_bind(struct device *dev)
 	if (ret)
 		goto err_poll_fini;
 
-	drm_fbdev_generic_setup(drm, legacyfb_depth);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, legacyfb_depth));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
index 8eb0ad501a7b..2e7815294e32 100644
--- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
+++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
@@ -1388,7 +1388,7 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
 		goto err_clk_notifier_unregister;
 	}
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/mcde/mcde_drv.c b/drivers/gpu/drm/mcde/mcde_drv.c
index e601baa87e55..e2ca0162061f 100644
--- a/drivers/gpu/drm/mcde/mcde_drv.c
+++ b/drivers/gpu/drm/mcde/mcde_drv.c
@@ -238,7 +238,7 @@ static int mcde_drm_bind(struct device *dev)
 	if (ret < 0)
 		goto unbind;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 247c6ff277ef..fef2cc840baf 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -393,7 +393,7 @@ static int mtk_drm_bind(struct device *dev)
 	if (ret < 0)
 		goto err_deinit;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 1b70938cfd2c..87fcee9143a9 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -350,7 +350,7 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
 	if (ret)
 		goto uninstall_irq;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 9d71c55a31c0..6b251916a6c9 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -357,7 +357,7 @@ static int mxsfb_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_unload;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c
index 520301b405f1..11b5aea3a166 100644
--- a/drivers/gpu/drm/pl111/pl111_drv.c
+++ b/drivers/gpu/drm/pl111/pl111_drv.c
@@ -308,7 +308,7 @@ static int pl111_amba_probe(struct amba_device *amba_dev,
 	if (ret < 0)
 		goto dev_put;
 
-	drm_fbdev_generic_setup(drm, priv->variant->fb_bpp);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, priv->variant->fb_bpp));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
index 1cb6f0c224bb..883beebe6317 100644
--- a/drivers/gpu/drm/qxl/qxl_drv.c
+++ b/drivers/gpu/drm/qxl/qxl_drv.c
@@ -122,7 +122,7 @@ qxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (ret)
 		goto modeset_cleanup;
 
-	drm_fbdev_generic_setup(&qdev->ddev, 32);
+	drm_fbdev_generic_setup(&qdev->ddev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 	return 0;
 
 modeset_cleanup:
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
index 957ea97541d5..6faadab6577b 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
@@ -681,7 +681,7 @@ static int rcar_du_probe(struct platform_device *pdev)
 
 	DRM_INFO("Device %s probed\n", dev_name(&pdev->dev));
 
-	drm_fbdev_generic_setup(&rcdu->ddev, 32);
+	drm_fbdev_generic_setup(&rcdu->ddev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/sti/sti_drv.c b/drivers/gpu/drm/sti/sti_drv.c
index d858209cf8de..b97ab614d25a 100644
--- a/drivers/gpu/drm/sti/sti_drv.c
+++ b/drivers/gpu/drm/sti/sti_drv.c
@@ -200,7 +200,7 @@ static int sti_bind(struct device *dev)
 
 	drm_mode_config_reset(ddev);
 
-	drm_fbdev_generic_setup(ddev, 32);
+	drm_fbdev_generic_setup(ddev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
index 0da7cce2a1a2..a04a54d0cc9a 100644
--- a/drivers/gpu/drm/stm/drv.c
+++ b/drivers/gpu/drm/stm/drv.c
@@ -203,7 +203,7 @@ static int stm_drm_platform_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_put;
 
-	drm_fbdev_generic_setup(ddev, 16);
+	drm_fbdev_generic_setup(ddev, DRM_FB_OPTION(DRM_FB_BPP, 16));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c b/drivers/gpu/drm/sun4i/sun4i_drv.c
index 275f7e4a03ae..f593a8d127fa 100644
--- a/drivers/gpu/drm/sun4i/sun4i_drv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
@@ -112,7 +112,7 @@ static int sun4i_drv_bind(struct device *dev)
 	if (ret)
 		goto finish_poll;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/tidss/tidss_drv.c b/drivers/gpu/drm/tidss/tidss_drv.c
index 04cfff89ee51..58f0d69b2979 100644
--- a/drivers/gpu/drm/tidss/tidss_drv.c
+++ b/drivers/gpu/drm/tidss/tidss_drv.c
@@ -180,7 +180,7 @@ static int tidss_probe(struct platform_device *pdev)
 		goto err_irq_uninstall;
 	}
 
-	drm_fbdev_generic_setup(ddev, 32);
+	drm_fbdev_generic_setup(ddev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	dev_dbg(dev, "%s done\n", __func__);
 
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
index eee3c447fbac..5216365ccab5 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
@@ -384,7 +384,7 @@ static int tilcdc_init(const struct drm_driver *ddrv, struct device *dev)
 		goto init_failed;
 	priv->is_registered = true;
 
-	drm_fbdev_generic_setup(ddev, bpp);
+	drm_fbdev_generic_setup(ddev, DRM_FB_OPTION(DRM_FB_BPP, bpp));
 	return 0;
 
 init_failed:
diff --git a/drivers/gpu/drm/tiny/arcpgu.c b/drivers/gpu/drm/tiny/arcpgu.c
index f0fa3b15c341..df989d5ff5a0 100644
--- a/drivers/gpu/drm/tiny/arcpgu.c
+++ b/drivers/gpu/drm/tiny/arcpgu.c
@@ -392,7 +392,7 @@ static int arcpgu_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_unload;
 
-	drm_fbdev_generic_setup(&arcpgu->drm, 16);
+	drm_fbdev_generic_setup(&arcpgu->drm, DRM_FB_OPTION(DRM_FB_BPP, 16));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index ed971c8bb446..c99608f20bcc 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -663,7 +663,7 @@ static int bochs_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent
 	if (ret)
 		goto err_free_dev;
 
-	drm_fbdev_generic_setup(dev, 32);
+	drm_fbdev_generic_setup(dev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 	return ret;
 
 err_free_dev:
diff --git a/drivers/gpu/drm/tve200/tve200_drv.c b/drivers/gpu/drm/tve200/tve200_drv.c
index 6d9d2921abf4..5fc940d09043 100644
--- a/drivers/gpu/drm/tve200/tve200_drv.c
+++ b/drivers/gpu/drm/tve200/tve200_drv.c
@@ -226,7 +226,7 @@ static int tve200_probe(struct platform_device *pdev)
 	 * Passing in 16 here will make the RGB565 mode the default
 	 * Passing in 32 will use XRGB8888 mode
 	 */
-	drm_fbdev_generic_setup(drm, 16);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 16));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/vboxvideo/vbox_drv.c b/drivers/gpu/drm/vboxvideo/vbox_drv.c
index f4f2bd79a7cb..2212be1bf03e 100644
--- a/drivers/gpu/drm/vboxvideo/vbox_drv.c
+++ b/drivers/gpu/drm/vboxvideo/vbox_drv.c
@@ -79,7 +79,7 @@ static int vbox_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (ret)
 		goto err_irq_fini;
 
-	drm_fbdev_generic_setup(&vbox->ddev, 32);
+	drm_fbdev_generic_setup(&vbox->ddev, DRM_FB_OPTION(DRM_FB_BPP, 32));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 162bc18e7497..ddfdf9907344 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -291,7 +291,7 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret < 0)
 		goto unbind_all;
 
-	drm_fbdev_generic_setup(drm, 16);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 16));
 
 	return 0;
 
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 5f25a8d15464..d62aa084392b 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -128,7 +128,7 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
 	if (ret)
 		goto err_deinit;
 
-	drm_fbdev_generic_setup(vdev->priv, 32);
+	drm_fbdev_generic_setup(vdev->priv, DRM_FB_OPTION(DRM_FB_BPP, 32));
 	return 0;
 
 err_deinit:
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dpsub.c b/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
index 824b510e337b..be1f0f6b460b 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dpsub.c
@@ -135,7 +135,7 @@ static int zynqmp_dpsub_drm_init(struct zynqmp_dpsub *dpsub)
 		goto err_poll_fini;
 
 	/* Initialize fbdev generic emulation. */
-	drm_fbdev_generic_setup(drm, 24);
+	drm_fbdev_generic_setup(drm, DRM_FB_OPTION(DRM_FB_BPP, 24));
 
 	return 0;
 
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 3af4624368d8..5fc41cf0c987 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -35,6 +35,7 @@ struct drm_fb_helper;
 #include <drm/drm_client.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_device.h>
+#include <linux/bitfield.h>
 #include <linux/kgdb.h>
 
 enum mode_set_atomic {
@@ -42,6 +43,17 @@ enum mode_set_atomic {
 	ENTER_ATOMIC_MODE_SET,
 };
 
+#define DRM_FB_BPP_MASK GENMASK(7, 0)
+
+/* Using the GNU statement expression extension */
+#define DRM_FB_OPTION(option, value)				\
+	({							\
+		WARN_ON(!FIELD_FIT(option##_MASK, value));	\
+		FIELD_PREP(option##_MASK, value);		\
+	})
+
+#define DRM_FB_GET_OPTION(option, word) FIELD_GET(option##_MASK, word)
+
 /**
  * struct drm_fb_helper_surface_size - describes fbdev size and scanout surface size
  * @fb_width: fbdev width
@@ -269,7 +281,7 @@ void drm_fb_helper_lastclose(struct drm_device *dev);
 void drm_fb_helper_output_poll_changed(struct drm_device *dev);
 
 void drm_fbdev_generic_setup(struct drm_device *dev,
-			     unsigned int preferred_bpp);
+			     const unsigned int options);
 #else
 static inline void drm_fb_helper_prepare(struct drm_device *dev,
 					struct drm_fb_helper *helper,
-- 
2.35.1

[PATCH v3 3/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[Javier Martinez Canillas]

Indicate to fbdev subsystem that the registered framebuffer is provided by
the system firmware, so that it can handle accordingly. For example, would
unregister the FB devices if asked to remove the conflicting framebuffers.

Add a new DRM_FB_FW field to drm_fbdev_generic_setup() options parameter.
Drivers can use this to indicate the FB helper initialization that the FB
registered is provided by the firmware, so it can be configured as such.

Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---

Changes in v3:
- Drop the firmware local variable (Laurent Pinchart).
- Use DRM_FB_OPTION() since DRM_FB_SET_OPTION() got renamed (kernel test robot).

 drivers/gpu/drm/drm_fb_helper.c  |  8 ++++++++
 drivers/gpu/drm/tiny/simpledrm.c |  2 +-
 include/drm/drm_fb_helper.h      | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 52042ba1e4cf..28b21858b726 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1891,6 +1891,10 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper,
 		/* don't leak any physical addresses to userspace */
 		info->flags |= FBINFO_HIDE_SMEM_START;
 
+	/* Indicate that the framebuffer is provided by the firmware */
+	if (fb_helper->firmware)
+		info->flags |= FBINFO_MISC_FIRMWARE;
+
 	/* Need to drop locks to avoid recursive deadlock in
 	 * register_framebuffer. This is ok because the only thing left to do is
 	 * register the fbdev emulation instance in kernel_fb_helper_list. */
@@ -2512,6 +2516,8 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = {
  *
  * * DRM_FB_BPP: bits per pixel for the device. If the field is not set,
  *   @dev->mode_config.preferred_depth is used instead.
+ * * DRM_FB_FW: if the framebuffer for the device is provided by the
+ *   system firmware.
  *
  * This function sets up generic fbdev emulation for drivers that supports
  * dumb buffers with a virtual address and that can be mmap'ed.
@@ -2569,6 +2575,8 @@ void drm_fbdev_generic_setup(struct drm_device *dev, const unsigned int options)
 	if (!fb_helper->preferred_bpp)
 		fb_helper->preferred_bpp = 32;
 
+	fb_helper->firmware = DRM_FB_GET_OPTION(DRM_FB_FW, options);
+
 	ret = drm_fbdev_client_hotplug(&fb_helper->client);
 	if (ret)
 		drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);
diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index f5b8e864a5cd..f6f1c5e108b2 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -901,7 +901,7 @@ static int simpledrm_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	drm_fbdev_generic_setup(dev, 0);
+	drm_fbdev_generic_setup(dev, DRM_FB_OPTION(DRM_FB_FW, 1));
 
 	return 0;
 }
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 5fc41cf0c987..5a17af423944 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -44,6 +44,7 @@ enum mode_set_atomic {
 };
 
 #define DRM_FB_BPP_MASK GENMASK(7, 0)
+#define DRM_FB_FW_MASK GENMASK(8, 8)
 
 /* Using the GNU statement expression extension */
 #define DRM_FB_OPTION(option, value)				\
@@ -197,6 +198,15 @@ struct drm_fb_helper {
 	 * See also: @deferred_setup
 	 */
 	int preferred_bpp;
+
+	/**
+	 * @firmware:
+	 *
+	 * Set if the driver indicates to the FB helper initialization that the
+	 * framebuffer for the device being registered is provided by firmware,
+	 * so that it can pass this on when registering the framebuffer device.
+	 */
+	bool firmware;
 };
 
 static inline struct drm_fb_helper *
-- 
2.35.1

Re: [PATCH v3 2/3] drm/fb-helper: Rename preferred_bpp drm_fbdev_generic_setup() parameter

[Jernej Škrabec]

Dne torek, 03. maj 2022 ob 09:15:39 CEST je Javier Martinez Canillas 
napisal(a):
> By default the bits per pixel for the emulated framebuffer device is set
> to dev->mode_config.preferred_depth, but some devices need another value.
> 
> Since this second parameter is only used by a few drivers, and to allow
> drivers to use it for passing other configurations when registering the
> fbdev, rename @preferred_bpp to @options and make it a multi-field param.
> 
> The DRM_FB_OPTION() and DRM_FB_GET_OPTION() macros are provided to drivers
> for computing options bitfield values and getting the values respectively
> 
> For now, only the DRM_FB_BPP option exists but other options can be added.
> 
> Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
> 
> Changes in v3:
> - Drop the preferred_bpp local variable (Laurent Pinchart).
> - Add a const qualifier to options parameter (Laurent Pinchart).
> 
> Changes in v2:
> - Rename DRM_FB_SET_OPTION() to DRM_FB_OPTION() and make more clear in
>   the kernel-doc what this macro does (Laurent Pinchart).
> - Fix some kernel-doc issues I didn't notice in v1.
> - Add Reviewed-by tags from Thomas and Laurent.
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |  6 +++--
>  drivers/gpu/drm/arm/hdlcd_drv.c               |  2 +-
>  drivers/gpu/drm/arm/malidp_drv.c              |  2 +-
>  drivers/gpu/drm/aspeed/aspeed_gfx_drv.c       |  2 +-
>  drivers/gpu/drm/ast/ast_drv.c                 |  2 +-
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c  |  2 +-
>  drivers/gpu/drm/drm_drv.c                     |  2 +-
>  drivers/gpu/drm/drm_fb_helper.c               | 26 ++++++++++++-------
>  drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c     |  2 +-
>  .../gpu/drm/hisilicon/kirin/kirin_drm_drv.c   |  2 +-
>  drivers/gpu/drm/imx/dcss/dcss-kms.c           |  2 +-
>  drivers/gpu/drm/imx/imx-drm-core.c            |  2 +-
>  drivers/gpu/drm/ingenic/ingenic-drm-drv.c     |  2 +-
>  drivers/gpu/drm/mcde/mcde_drv.c               |  2 +-
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c        |  2 +-
>  drivers/gpu/drm/meson/meson_drv.c             |  2 +-
>  drivers/gpu/drm/mxsfb/mxsfb_drv.c             |  2 +-
>  drivers/gpu/drm/pl111/pl111_drv.c             |  2 +-
>  drivers/gpu/drm/qxl/qxl_drv.c                 |  2 +-
>  drivers/gpu/drm/rcar-du/rcar_du_drv.c         |  2 +-
>  drivers/gpu/drm/sti/sti_drv.c                 |  2 +-
>  drivers/gpu/drm/stm/drv.c                     |  2 +-
>  drivers/gpu/drm/sun4i/sun4i_drv.c             |  2 +-

For sun4i:
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Best regard,
Jernej

>  drivers/gpu/drm/tidss/tidss_drv.c             |  2 +-
>  drivers/gpu/drm/tilcdc/tilcdc_drv.c           |  2 +-
>  drivers/gpu/drm/tiny/arcpgu.c                 |  2 +-
>  drivers/gpu/drm/tiny/bochs.c                  |  2 +-
>  drivers/gpu/drm/tve200/tve200_drv.c           |  2 +-
>  drivers/gpu/drm/vboxvideo/vbox_drv.c          |  2 +-
>  drivers/gpu/drm/vc4/vc4_drv.c                 |  2 +-
>  drivers/gpu/drm/virtio/virtgpu_drv.c          |  2 +-
>  drivers/gpu/drm/xlnx/zynqmp_dpsub.c           |  2 +-
>  include/drm/drm_fb_helper.h                   | 14 +++++++++-
>  33 files changed, 64 insertions(+), 42 deletions(-)

Re: [PATCH v3 3/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[Daniel Vetter]

On Tue, May 03, 2022 at 09:15:40AM +0200, Javier Martinez Canillas wrote:
> Indicate to fbdev subsystem that the registered framebuffer is provided by
> the system firmware, so that it can handle accordingly. For example, would
> unregister the FB devices if asked to remove the conflicting framebuffers.
> 
> Add a new DRM_FB_FW field to drm_fbdev_generic_setup() options parameter.
> Drivers can use this to indicate the FB helper initialization that the FB
> registered is provided by the firmware, so it can be configured as such.
> 
> Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
> 
> Changes in v3:
> - Drop the firmware local variable (Laurent Pinchart).
> - Use DRM_FB_OPTION() since DRM_FB_SET_OPTION() got renamed (kernel test robot).

Just for the record what I brought up on irc already:

FBINFO_MISC_FIRMWARE is purely an internal flag with no uapi impact, and
it's only to control whether we nuke this from
remove_conflicting_framebuffer or not. Since simpledrm only ever binds
against sysfb I think it'd be cleaner to only rely on that, and relegate
that entire FBINFO_MISC_FIRMWARE misc hack to the fbdev dungeons and let
it quietly wither away there.

Also I'm not a huge fan of these midlayer flags in general :-)
-Daniel

> 
>  drivers/gpu/drm/drm_fb_helper.c  |  8 ++++++++
>  drivers/gpu/drm/tiny/simpledrm.c |  2 +-
>  include/drm/drm_fb_helper.h      | 10 ++++++++++
>  3 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 52042ba1e4cf..28b21858b726 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1891,6 +1891,10 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper,
>  		/* don't leak any physical addresses to userspace */
>  		info->flags |= FBINFO_HIDE_SMEM_START;
>  
> +	/* Indicate that the framebuffer is provided by the firmware */
> +	if (fb_helper->firmware)
> +		info->flags |= FBINFO_MISC_FIRMWARE;
> +
>  	/* Need to drop locks to avoid recursive deadlock in
>  	 * register_framebuffer. This is ok because the only thing left to do is
>  	 * register the fbdev emulation instance in kernel_fb_helper_list. */
> @@ -2512,6 +2516,8 @@ static const struct drm_client_funcs drm_fbdev_client_funcs = {
>   *
>   * * DRM_FB_BPP: bits per pixel for the device. If the field is not set,
>   *   @dev->mode_config.preferred_depth is used instead.
> + * * DRM_FB_FW: if the framebuffer for the device is provided by the
> + *   system firmware.
>   *
>   * This function sets up generic fbdev emulation for drivers that supports
>   * dumb buffers with a virtual address and that can be mmap'ed.
> @@ -2569,6 +2575,8 @@ void drm_fbdev_generic_setup(struct drm_device *dev, const unsigned int options)
>  	if (!fb_helper->preferred_bpp)
>  		fb_helper->preferred_bpp = 32;
>  
> +	fb_helper->firmware = DRM_FB_GET_OPTION(DRM_FB_FW, options);
> +
>  	ret = drm_fbdev_client_hotplug(&fb_helper->client);
>  	if (ret)
>  		drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);
> diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
> index f5b8e864a5cd..f6f1c5e108b2 100644
> --- a/drivers/gpu/drm/tiny/simpledrm.c
> +++ b/drivers/gpu/drm/tiny/simpledrm.c
> @@ -901,7 +901,7 @@ static int simpledrm_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	drm_fbdev_generic_setup(dev, 0);
> +	drm_fbdev_generic_setup(dev, DRM_FB_OPTION(DRM_FB_FW, 1));
>  
>  	return 0;
>  }
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index 5fc41cf0c987..5a17af423944 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -44,6 +44,7 @@ enum mode_set_atomic {
>  };
>  
>  #define DRM_FB_BPP_MASK GENMASK(7, 0)
> +#define DRM_FB_FW_MASK GENMASK(8, 8)
>  
>  /* Using the GNU statement expression extension */
>  #define DRM_FB_OPTION(option, value)				\
> @@ -197,6 +198,15 @@ struct drm_fb_helper {
>  	 * See also: @deferred_setup
>  	 */
>  	int preferred_bpp;
> +
> +	/**
> +	 * @firmware:
> +	 *
> +	 * Set if the driver indicates to the FB helper initialization that the
> +	 * framebuffer for the device being registered is provided by firmware,
> +	 * so that it can pass this on when registering the framebuffer device.
> +	 */
> +	bool firmware;
>  };
>  
>  static inline struct drm_fb_helper *
> -- 
> 2.35.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v3 3/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[Javier Martinez Canillas]

On 5/4/22 12:58, Daniel Vetter wrote:
> On Tue, May 03, 2022 at 09:15:40AM +0200, Javier Martinez Canillas wrote:
>> Indicate to fbdev subsystem that the registered framebuffer is provided by
>> the system firmware, so that it can handle accordingly. For example, would
>> unregister the FB devices if asked to remove the conflicting framebuffers.
>>
>> Add a new DRM_FB_FW field to drm_fbdev_generic_setup() options parameter.
>> Drivers can use this to indicate the FB helper initialization that the FB
>> registered is provided by the firmware, so it can be configured as such.
>>
>> Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
>> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
>> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
>> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>> ---
>>
>> Changes in v3:
>> - Drop the firmware local variable (Laurent Pinchart).
>> - Use DRM_FB_OPTION() since DRM_FB_SET_OPTION() got renamed (kernel test robot).
> 
> Just for the record what I brought up on irc already:
> 
> FBINFO_MISC_FIRMWARE is purely an internal flag with no uapi impact, and
> it's only to control whether we nuke this from
> remove_conflicting_framebuffer or not. Since simpledrm only ever binds
> against sysfb I think it'd be cleaner to only rely on that, and relegate

That's not actually true. The OF subsystem also registers "simple-framebuffer"
devices when there are Device Tree nodes that contain a "simple-framebuffer"
compatible string. In that case these pdev will also bind against simpledrm.

> that entire FBINFO_MISC_FIRMWARE misc hack to the fbdev dungeons and let
> it quietly wither away there.
>
> Also I'm not a huge fan of these midlayer flags in general :-)

And while I agree with you that these midlayer flags are horrible, that is
what any other fbdev that makes use of a firmware-provided framebuffer set,
so simpledrm emulated fbdev shouldn't be the exception IMO.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH v3 3/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[Daniel Vetter]

On Wed, May 04, 2022 at 01:32:37PM +0200, Javier Martinez Canillas wrote:
> On 5/4/22 12:58, Daniel Vetter wrote:
> > On Tue, May 03, 2022 at 09:15:40AM +0200, Javier Martinez Canillas wrote:
> >> Indicate to fbdev subsystem that the registered framebuffer is provided by
> >> the system firmware, so that it can handle accordingly. For example, would
> >> unregister the FB devices if asked to remove the conflicting framebuffers.
> >>
> >> Add a new DRM_FB_FW field to drm_fbdev_generic_setup() options parameter.
> >> Drivers can use this to indicate the FB helper initialization that the FB
> >> registered is provided by the firmware, so it can be configured as such.
> >>
> >> Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
> >> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> >> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
> >> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >> ---
> >>
> >> Changes in v3:
> >> - Drop the firmware local variable (Laurent Pinchart).
> >> - Use DRM_FB_OPTION() since DRM_FB_SET_OPTION() got renamed (kernel test robot).
> > 
> > Just for the record what I brought up on irc already:
> > 
> > FBINFO_MISC_FIRMWARE is purely an internal flag with no uapi impact, and
> > it's only to control whether we nuke this from
> > remove_conflicting_framebuffer or not. Since simpledrm only ever binds
> > against sysfb I think it'd be cleaner to only rely on that, and relegate
> 
> That's not actually true. The OF subsystem also registers "simple-framebuffer"
> devices when there are Device Tree nodes that contain a "simple-framebuffer"
> compatible string. In that case these pdev will also bind against simpledrm.

TIL.

> > that entire FBINFO_MISC_FIRMWARE misc hack to the fbdev dungeons and let
> > it quietly wither away there.
> >
> > Also I'm not a huge fan of these midlayer flags in general :-)
> 
> And while I agree with you that these midlayer flags are horrible, that is
> what any other fbdev that makes use of a firmware-provided framebuffer set,
> so simpledrm emulated fbdev shouldn't be the exception IMO.

So we discussed this a pile more on irc, and at least my take is that
people who run simpledrm but want to combine that with fbdev drivers and
expect it to all work nicely we can probably ignore. At least until all
this sysfb stuff is nicely unified, and at that point we shouldn't need
special flags anymore.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH v3 3/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[Javier Martinez Canillas]

Hello Daniel,

On 5/5/22 14:11, Daniel Vetter wrote:

[snip]

>>
>> And while I agree with you that these midlayer flags are horrible, that is
>> what any other fbdev that makes use of a firmware-provided framebuffer set,
>> so simpledrm emulated fbdev shouldn't be the exception IMO.
> 
> So we discussed this a pile more on irc, and at least my take is that
> people who run simpledrm but want to combine that with fbdev drivers and
> expect it to all work nicely we can probably ignore. At least until all
> this sysfb stuff is nicely unified, and at that point we shouldn't need
> special flags anymore.

I'm OK with this take and happy to just drop this patch-set then. My worry
was just that someone could complain that we broke their uncommon setup [0].

[0]: https://xkcd.com/1172/.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH v3 3/3] drm: Allow simpledrm to setup its emulated FB as firmware provided

[Daniel Vetter]

On Thu, May 05, 2022 at 02:45:27PM +0200, Javier Martinez Canillas wrote:
> Hello Daniel,
> 
> On 5/5/22 14:11, Daniel Vetter wrote:
> 
> [snip]
> 
> >>
> >> And while I agree with you that these midlayer flags are horrible, that is
> >> what any other fbdev that makes use of a firmware-provided framebuffer set,
> >> so simpledrm emulated fbdev shouldn't be the exception IMO.
> > 
> > So we discussed this a pile more on irc, and at least my take is that
> > people who run simpledrm but want to combine that with fbdev drivers and
> > expect it to all work nicely we can probably ignore. At least until all
> > this sysfb stuff is nicely unified, and at that point we shouldn't need
> > special flags anymore.
> 
> I'm OK with this take and happy to just drop this patch-set then. My worry
> was just that someone could complain that we broke their uncommon setup [0].
> 
> [0]: https://xkcd.com/1172/.

Since you have to explicitly enable simpledrm and that combo never
worked, we did not actually break anything.

Me, who has over a decade experience legalesing around the "no regression"
rule :-)
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch