Re: [PATCH] drm: Remove drm_mode_config::fb_base

[Zack Rusin <zackr@vmware.com>]

On Tue, 2022-10-18 at 16:05 +0200, Thomas Zimmermann wrote:
> Hi
> 
> Am 18.10.22 um 15:17 schrieb Zack Rusin:
> > From: Zack Rusin <zackr@vmware.com>
> > 
> > The fb_base in struct drm_mode_config has been unused for a long time.
> > Some drivers set it and some don't leading to a very confusing state
> > where the variable can't be relied upon, because there's no indication
> > as to which driver sets it and which doesn't.
> > 
> > The only usage of fb_base is internal to two drivers so instead of trying
> > to force it into all the drivers to get it into a coherent state
> > completely remove it.
> 
> Thanks a lot. I wanted to remove that field for some time. Pleaser see 
> my comments below.
> 
> > 
> > Signed-off-by: Zack Rusin <zackr@vmware.com>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c          | 2 --
> >   drivers/gpu/drm/amd/amdgpu/dce_v10_0.c            | 2 --
> >   drivers/gpu/drm/amd/amdgpu/dce_v11_0.c            | 2 --
> >   drivers/gpu/drm/amd/amdgpu/dce_v6_0.c             | 1 -
> >   drivers/gpu/drm/amd/amdgpu/dce_v8_0.c             | 2 --
> >   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 --
> >   drivers/gpu/drm/ast/ast_mode.c                    | 1 -
> >   drivers/gpu/drm/gma500/framebuffer.c              | 6 +++---
> >   drivers/gpu/drm/gma500/psb_drv.h                  | 1 +
> >   drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c   | 1 -
> >   drivers/gpu/drm/mgag200/mgag200_mode.c            | 1 -
> >   drivers/gpu/drm/msm/msm_fbdev.c                   | 2 --
> >   drivers/gpu/drm/nouveau/nouveau_display.c         | 1 -
> >   drivers/gpu/drm/nouveau/nv04_fbcon.c              | 6 ++++--
> >   drivers/gpu/drm/omapdrm/omap_fbdev.c              | 2 --
> >   drivers/gpu/drm/qxl/qxl_display.c                 | 2 --
> >   drivers/gpu/drm/radeon/radeon_display.c           | 2 --
> >   drivers/gpu/drm/radeon/radeon_fb.c                | 1 -
> >   drivers/gpu/drm/tegra/fb.c                        | 1 -
> >   drivers/gpu/drm/tiny/bochs.c                      | 1 -
> >   include/drm/drm_mode_config.h                     | 2 --
> >   21 files changed, 8 insertions(+), 33 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
> > index f4b5301ea2a0..09dec2561adf 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
> > @@ -498,8 +498,6 @@ static int amdgpu_vkms_sw_init(void *handle)
> >   	adev_to_drm(adev)->mode_config.preferred_depth = 24;
> >   	adev_to_drm(adev)->mode_config.prefer_shadow = 1;
> >   
> > -	adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
> > -
> >   	r = amdgpu_display_modeset_create_props(adev);
> >   	if (r)
> >   		return r;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> > index 288fce7dc0ed..05051d5d2ec3 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> > @@ -2800,8 +2800,6 @@ static int dce_v10_0_sw_init(void *handle)
> >   
> >   	adev_to_drm(adev)->mode_config.fb_modifiers_not_supported = true;
> >   
> > -	adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
> > -
> >   	r = amdgpu_display_modeset_create_props(adev);
> >   	if (r)
> >   		return r;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> > index cbe5250b31cb..c928bc9eb202 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> > @@ -2918,8 +2918,6 @@ static int dce_v11_0_sw_init(void *handle)
> >   
> >   	adev_to_drm(adev)->mode_config.fb_modifiers_not_supported = true;
> >   
> > -	adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
> > -
> >   	r = amdgpu_display_modeset_create_props(adev);
> >   	if (r)
> >   		return r;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> > index b1c44fab074f..62315fd5a05f 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> > @@ -2675,7 +2675,6 @@ static int dce_v6_0_sw_init(void *handle)
> >   	adev_to_drm(adev)->mode_config.preferred_depth = 24;
> >   	adev_to_drm(adev)->mode_config.prefer_shadow = 1;
> >   	adev_to_drm(adev)->mode_config.fb_modifiers_not_supported = true;
> > -	adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
> >   
> >   	r = amdgpu_display_modeset_create_props(adev);
> >   	if (r)
> > diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> > index a22b45c92792..87d5e4c21cb3 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> > @@ -2701,8 +2701,6 @@ static int dce_v8_0_sw_init(void *handle)
> >   
> >   	adev_to_drm(adev)->mode_config.fb_modifiers_not_supported = true;
> >   
> > -	adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
> > -
> >   	r = amdgpu_display_modeset_create_props(adev);
> >   	if (r)
> >   		return r;
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > index c053cb79cd06..0db2a88cd4d7 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > @@ -3816,8 +3816,6 @@ static int amdgpu_dm_mode_config_init(struct amdgpu_device *adev)
> >   	/* indicates support for immediate flip */
> >   	adev_to_drm(adev)->mode_config.async_page_flip = true;
> >   
> > -	adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
> > -
> >   	state = kzalloc(sizeof(*state), GFP_KERNEL);
> >   	if (!state)
> >   		return -ENOMEM;
> > diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
> > index 4355754d69b5..1a01208d53d9 100644
> > --- a/drivers/gpu/drm/ast/ast_mode.c
> > +++ b/drivers/gpu/drm/ast/ast_mode.c
> > @@ -1778,7 +1778,6 @@ int ast_mode_config_init(struct ast_private *ast)
> >   	dev->mode_config.min_width = 0;
> >   	dev->mode_config.min_height = 0;
> >   	dev->mode_config.preferred_depth = 24;
> > -	dev->mode_config.fb_base = pci_resource_start(pdev, 0);
> >   
> >   	if (ast->chip == AST2100 ||
> >   	    ast->chip == AST2200 ||
> > diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
> > index aa3ecf771fd3..5f502a0048ab 100644
> > --- a/drivers/gpu/drm/gma500/framebuffer.c
> > +++ b/drivers/gpu/drm/gma500/framebuffer.c
> > @@ -286,7 +286,7 @@ static int psbfb_create(struct drm_fb_helper *fb_helper,
> >   
> >   	info->fbops = &psbfb_unaccel_ops;
> >   
> > -	info->fix.smem_start = dev->mode_config.fb_base;
> > +	info->fix.smem_start = dev_priv->fb_base;
> >   	info->fix.smem_len = size;
> >   	info->fix.ywrapstep = 0;
> >   	info->fix.ypanstep = 0;
> > @@ -296,7 +296,7 @@ static int psbfb_create(struct drm_fb_helper *fb_helper,
> >   	info->screen_size = size;
> >   
> >   	if (dev_priv->gtt.stolen_size) {
> > -		info->apertures->ranges[0].base = dev->mode_config.fb_base;
> > +		info->apertures->ranges[0].base = dev_priv->fb_base;
> >   		info->apertures->ranges[0].size = dev_priv->gtt.stolen_size;
> >   	}
> >   
> > @@ -527,7 +527,7 @@ void psb_modeset_init(struct drm_device *dev)
> >   
> >   	/* set memory base */
> >   	/* Oaktrail and Poulsbo should use BAR 2*/
> > -	pci_read_config_dword(pdev, PSB_BSM, (u32 *)&(dev->mode_config.fb_base));
> > +	pci_read_config_dword(pdev, PSB_BSM, (u32 *)&(dev_priv->fb_base));
> 
> Although probably correct, that code looks questionable. Maybe have a 
> local fb_base of type u32 and assign that to the field in dev_priv. It's 
> the safe variant.
> 

I thought the same, but I don't have a psb system to test so I opted to preserve
exactly what the code was doing before. fb_base in either case is a resource_size_t,
and I'm guessing the entire thing depends, in either case, on drm_psb_private being
kzalloc's. I'm happy to change to just use a local u32 but I can't test it so if
there's some side-effect to upper bits in fb_base in that driver we'll break it.

> >   
> >   	/* num pipes is 2 for PSB but 1 for Mrst */
> >   	for (i = 0; i < dev_priv->num_pipe; i++)
> > diff --git a/drivers/gpu/drm/gma500/psb_drv.h b/drivers/gpu/drm/gma500/psb_drv.h
> > index ae544b69fc47..a5df6d2f2cab 100644
> > --- a/drivers/gpu/drm/gma500/psb_drv.h
> > +++ b/drivers/gpu/drm/gma500/psb_drv.h
> > @@ -523,6 +523,7 @@ struct drm_psb_private {
> >   	uint32_t blc_adj2;
> >   
> >   	struct drm_fb_helper *fb_helper;
> > +	resource_size_t fb_base;
> >   
> >   	bool dsr_enable;
> >   	u32 dsr_fb_update;
> > diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> > index fe4269c5aa0a..2293038755c5 100644
> > --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> > +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> > @@ -105,7 +105,6 @@ static int hibmc_kms_init(struct hibmc_drm_private *priv)
> >   	dev->mode_config.max_width = 1920;
> >   	dev->mode_config.max_height = 1200;
> >   
> > -	dev->mode_config.fb_base = priv->fb_base;
> >   	dev->mode_config.preferred_depth = 32;
> >   	dev->mode_config.prefer_shadow = 1;
> >   
> > diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
> > index 758629da95d9..0a5aaf78172a 100644
> > --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
> > +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
> > @@ -824,7 +824,6 @@ int mgag200_mode_config_init(struct mga_device *mdev, resource_size_t vram_avail
> >   	dev->mode_config.max_width = MGAG200_MAX_FB_WIDTH;
> >   	dev->mode_config.max_height = MGAG200_MAX_FB_HEIGHT;
> >   	dev->mode_config.preferred_depth = 24;
> > -	dev->mode_config.fb_base = mdev->vram_res->start;
> >   	dev->mode_config.funcs = &mgag200_mode_config_funcs;
> >   	dev->mode_config.helper_private = &mgag200_mode_config_helper_funcs;
> >   
> > diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
> > index 46168eccfac4..b373e3000320 100644
> > --- a/drivers/gpu/drm/msm/msm_fbdev.c
> > +++ b/drivers/gpu/drm/msm/msm_fbdev.c
> > @@ -109,8 +109,6 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
> >   
> >   	drm_fb_helper_fill_info(fbi, helper, sizes);
> >   
> > -	dev->mode_config.fb_base = paddr;
> > -
> >   	fbi->screen_base = msm_gem_get_vaddr(bo);
> >   	if (IS_ERR(fbi->screen_base)) {
> >   		ret = PTR_ERR(fbi->screen_base);
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c
> > index a2f5df568ca5..928fdfa8e8e5 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_display.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_display.c
> > @@ -672,7 +672,6 @@ nouveau_display_create(struct drm_device *dev)
> >   	drm_mode_create_dvi_i_properties(dev);
> >   
> >   	dev->mode_config.funcs = &nouveau_mode_config_funcs;
> > -	dev->mode_config.fb_base = device->func->resource_addr(device, 1);
> >   
> >   	dev->mode_config.min_width = 0;
> >   	dev->mode_config.min_height = 0;
> > diff --git a/drivers/gpu/drm/nouveau/nv04_fbcon.c b/drivers/gpu/drm/nouveau/nv04_fbcon.c
> > index 92f3fb6765ab..c30b8dacd86b 100644
> > --- a/drivers/gpu/drm/nouveau/nv04_fbcon.c
> > +++ b/drivers/gpu/drm/nouveau/nv04_fbcon.c
> > @@ -137,6 +137,8 @@ nv04_fbcon_accel_init(struct fb_info *info)
> >   	struct nouveau_channel *chan = drm->channel;
> >   	struct nvif_device *device = &drm->client.device;
> >   	struct nvif_push *push = chan->chan.push;
> > +	struct nvkm_device *nvkm_device = nvxx_device(&drm->client.device);
> > +	resource_size_t fb_base = nvkm_device->func->resource_addr(nvkm_device, 1);
> >   	int surface_fmt, pattern_fmt, rect_fmt;
> >   	int ret;
> >   
> > @@ -210,8 +212,8 @@ nv04_fbcon_accel_init(struct fb_info *info)
> >   			       0x0188, chan->vram.handle);
> >   	PUSH_NVSQ(push, NV042, 0x0300, surface_fmt,
> >   			       0x0304, info->fix.line_length | (info->fix.line_length << 16),
> > -			       0x0308, info->fix.smem_start - dev->mode_config.fb_base,
> > -			       0x030c, info->fix.smem_start - dev->mode_config.fb_base);
> > +			       0x0308, info->fix.smem_start - fb_base,
> > +			       0x030c, info->fix.smem_start - fb_base);
> >   
> >   	PUSH_NVSQ(push, NV043, 0x0000, nfbdev->rop.handle);
> >   	PUSH_NVSQ(push, NV043, 0x0300, 0x55);
> > diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> > index 40706c5aad7b..ed67dd25794c 100644
> > --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> > +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> > @@ -177,8 +177,6 @@ static int omap_fbdev_create(struct drm_fb_helper *helper,
> >   
> >   	drm_fb_helper_fill_info(fbi, helper, sizes);
> >   
> > -	dev->mode_config.fb_base = dma_addr;
> > -
> >   	fbi->screen_buffer = omap_gem_vaddr(fbdev->bo);
> >   	fbi->screen_size = fbdev->bo->size;
> >   	fbi->fix.smem_start = dma_addr;
> > diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
> > index a152a7c6db21..6492a70e3c39 100644
> > --- a/drivers/gpu/drm/qxl/qxl_display.c
> > +++ b/drivers/gpu/drm/qxl/qxl_display.c
> > @@ -1261,8 +1261,6 @@ int qxl_modeset_init(struct qxl_device *qdev)
> >   	qdev->ddev.mode_config.max_width = 8192;
> >   	qdev->ddev.mode_config.max_height = 8192;
> >   
> > -	qdev->ddev.mode_config.fb_base = qdev->vram_base;
> > -
> >   	drm_mode_create_suggested_offset_properties(&qdev->ddev);
> >   	qxl_mode_create_hotplug_mode_update_property(qdev);
> >   
> > diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
> > index ca5598ae8bfc..9bed1a6cb163 100644
> > --- a/drivers/gpu/drm/radeon/radeon_display.c
> > +++ b/drivers/gpu/drm/radeon/radeon_display.c
> > @@ -1604,8 +1604,6 @@ int radeon_modeset_init(struct radeon_device *rdev)
> >   
> >   	rdev->ddev->mode_config.fb_modifiers_not_supported = true;
> >   
> > -	rdev->ddev->mode_config.fb_base = rdev->mc.aper_base;
> > -
> >   	ret = radeon_modeset_create_props(rdev);
> >   	if (ret) {
> >   		return ret;
> > diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
> > index 6ccea51d4072..df33e3a87c92 100644
> > --- a/drivers/gpu/drm/radeon/radeon_fb.c
> > +++ b/drivers/gpu/drm/radeon/radeon_fb.c
> > @@ -276,7 +276,6 @@ static int radeonfb_create(struct drm_fb_helper *helper,
> >   	drm_fb_helper_fill_info(info, &rfbdev->helper, sizes);
> >   
> >   	/* setup aperture base/size for vesafb takeover */
> > -	info->apertures->ranges[0].base = rdev->ddev->mode_config.fb_base;
> 
> Don't you have to assign 'rdev->mc.aper_base' here?

Yes! Good catch. Missed that. v2 coming.

z