[PATCH] drm: Introduce drm_fb_helper_prepare()
Daniel Vetter
daniel at ffwll.ch
Wed Apr 23 07:24:35 PDT 2014
On Wed, Apr 23, 2014 at 03:40:46PM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding at nvidia.com>
>
> To implement hotplug detection in a race-free manner, drivers must call
> drm_kms_helper_poll_init() before hotplug events can be triggered. Such
> events can be triggered right after any of the encoders or connectors
> are initialized. At the same time, if the drm_fb_helper_hotplug_event()
> helper is used by a driver, then the poll helper requires some parts of
> the FB helper to be initialized to prevent a crash.
>
> At the same time, drm_fb_helper_init() requires information that is not
> necessarily available at such an early stage (number of CRTCs and
> connectors), so it cannot be used yet.
>
> Add a new helper, drm_fb_helper_prepare(), that initializes the bare
> minimum needed to allow drm_kms_helper_poll_init() to execute and any
> subsequent hotplug events to be processed properly.
>
> Signed-off-by: Thierry Reding <treding at nvidia.com>
> ---
> Changes in v2:
> - improve kernel-doc (Daniel Vetter)
>
> drivers/gpu/drm/armada/armada_fbdev.c | 2 +-
> drivers/gpu/drm/ast/ast_fb.c | 4 ++-
> drivers/gpu/drm/bochs/bochs_fbdev.c | 3 +-
> drivers/gpu/drm/cirrus/cirrus_fbdev.c | 4 ++-
> drivers/gpu/drm/drm_fb_cma_helper.c | 3 +-
> drivers/gpu/drm/drm_fb_helper.c | 47 ++++++++++++++++++++++++-------
> drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 3 +-
> drivers/gpu/drm/gma500/framebuffer.c | 3 +-
> drivers/gpu/drm/i915/intel_fbdev.c | 3 +-
> drivers/gpu/drm/mgag200/mgag200_fb.c | 3 +-
> drivers/gpu/drm/msm/msm_fbdev.c | 2 +-
> drivers/gpu/drm/nouveau/nouveau_fbcon.c | 3 +-
> drivers/gpu/drm/omapdrm/omap_fbdev.c | 2 +-
> drivers/gpu/drm/qxl/qxl_fb.c | 5 +++-
> drivers/gpu/drm/radeon/radeon_fb.c | 4 ++-
> drivers/gpu/drm/tegra/fb.c | 4 +--
> drivers/gpu/drm/udl/udl_fb.c | 3 +-
> include/drm/drm_fb_helper.h | 2 ++
> 18 files changed, 72 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
> index 21aa1261dba2..9437e11d5df1 100644
> --- a/drivers/gpu/drm/armada/armada_fbdev.c
> +++ b/drivers/gpu/drm/armada/armada_fbdev.c
> @@ -149,7 +149,7 @@ int armada_fbdev_init(struct drm_device *dev)
>
> priv->fbdev = fbh;
>
> - fbh->funcs = &armada_fb_helper_funcs;
> + drm_fb_helper_prepare(dev, fbh, &armada_fb_helper_funcs);
>
> ret = drm_fb_helper_init(dev, fbh, 1, 1);
> if (ret) {
> diff --git a/drivers/gpu/drm/ast/ast_fb.c b/drivers/gpu/drm/ast/ast_fb.c
> index 2113894e4ff8..cba45c774552 100644
> --- a/drivers/gpu/drm/ast/ast_fb.c
> +++ b/drivers/gpu/drm/ast/ast_fb.c
> @@ -328,8 +328,10 @@ int ast_fbdev_init(struct drm_device *dev)
> return -ENOMEM;
>
> ast->fbdev = afbdev;
> - afbdev->helper.funcs = &ast_fb_helper_funcs;
> spin_lock_init(&afbdev->dirty_lock);
> +
> + drm_fb_helper_prepare(dev, &afbdev->helper, &ast_fb_helper_funcs);
> +
> ret = drm_fb_helper_init(dev, &afbdev->helper,
> 1, 1);
> if (ret) {
> diff --git a/drivers/gpu/drm/bochs/bochs_fbdev.c b/drivers/gpu/drm/bochs/bochs_fbdev.c
> index 17e5c17f2730..19cf3e9413b6 100644
> --- a/drivers/gpu/drm/bochs/bochs_fbdev.c
> +++ b/drivers/gpu/drm/bochs/bochs_fbdev.c
> @@ -189,7 +189,8 @@ int bochs_fbdev_init(struct bochs_device *bochs)
> {
> int ret;
>
> - bochs->fb.helper.funcs = &bochs_fb_helper_funcs;
> + drm_fb_helper_prepare(bochs->dev, &bochs->fb.helper,
> + &bochs_fb_helper_funcs);
>
> ret = drm_fb_helper_init(bochs->dev, &bochs->fb.helper,
> 1, 1);
> diff --git a/drivers/gpu/drm/cirrus/cirrus_fbdev.c b/drivers/gpu/drm/cirrus/cirrus_fbdev.c
> index 2bd0291168e4..2a135f253e29 100644
> --- a/drivers/gpu/drm/cirrus/cirrus_fbdev.c
> +++ b/drivers/gpu/drm/cirrus/cirrus_fbdev.c
> @@ -306,9 +306,11 @@ int cirrus_fbdev_init(struct cirrus_device *cdev)
> return -ENOMEM;
>
> cdev->mode_info.gfbdev = gfbdev;
> - gfbdev->helper.funcs = &cirrus_fb_helper_funcs;
> spin_lock_init(&gfbdev->dirty_lock);
>
> + drm_fb_helper_prepare(cdev->dev, &gfbdev->helper,
> + &cirrus_fb_helper_funcs);
> +
> ret = drm_fb_helper_init(cdev->dev, &gfbdev->helper,
> cdev->num_crtc, CIRRUSFB_CONN_LIMIT);
> if (ret) {
> diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c
> index b74f9e58b69d..acbbd230e081 100644
> --- a/drivers/gpu/drm/drm_fb_cma_helper.c
> +++ b/drivers/gpu/drm/drm_fb_cma_helper.c
> @@ -354,9 +354,10 @@ struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev,
> return ERR_PTR(-ENOMEM);
> }
>
> - fbdev_cma->fb_helper.funcs = &drm_fb_cma_helper_funcs;
> helper = &fbdev_cma->fb_helper;
>
> + drm_fb_helper_prepare(dev, helper, &drm_fb_cma_helper_funcs);
> +
> ret = drm_fb_helper_init(dev, helper, num_crtc, max_conn_count);
> if (ret < 0) {
> dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 80ce92ab91f9..5e87b4b638db 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -49,10 +49,11 @@ static LIST_HEAD(kernel_fb_helper_list);
> * helper functions used by many drivers to implement the kernel mode setting
> * interfaces.
> *
> - * Initialization is done as a three-step process with drm_fb_helper_init(),
> - * drm_fb_helper_single_add_all_connectors() and drm_fb_helper_initial_config().
> - * Drivers with fancier requirements than the default behaviour can override the
> - * second step with their own code. Teardown is done with drm_fb_helper_fini().
> + * Initialization is done as a four-step process with drm_fb_helper_prepare(),
> + * drm_fb_helper_init(), drm_fb_helper_single_add_all_connectors() and
> + * drm_fb_helper_initial_config(). Drivers with fancier requirements than the
> + * default behaviour can override the second step with their own code.
s/second/third/
Otherwise the new kerneldoc looks nice, so presuming you didn't touch the
code this is still (with the above fixed ofc)
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> + * Teardown is done with drm_fb_helper_fini().
> *
> * At runtime drivers should restore the fbdev console by calling
> * drm_fb_helper_restore_fbdev_mode() from their ->lastclose callback. They
> @@ -63,6 +64,19 @@ static LIST_HEAD(kernel_fb_helper_list);
> *
> * All other functions exported by the fb helper library can be used to
> * implement the fbdev driver interface by the driver.
> + *
> + * It is possible, though perhaps somewhat tricky, to implement race-free
> + * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
> + * helper must be called first to initialize the minimum required to make
> + * hotplug detection work. Drivers also need to make sure to properly set up
> + * the dev->mode_config.funcs member. After calling drm_kms_helper_poll_init()
> + * it is safe to enable interrupts and start processing hotplug events. At the
> + * same time, drivers should initialize all modeset objects such as CRTCs,
> + * encoders and connectors. To finish up the fbdev helper initialization, the
> + * drm_fb_helper_init() function is called. To probe for all attached displays
> + * and set up an initial configuration using the detected hardware, drivers
> + * should call drm_fb_helper_single_add_all_connectors() followed by
> + * drm_fb_helper_initial_config().
> */
>
> /**
> @@ -502,6 +516,24 @@ static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
> }
>
> /**
> + * drm_fb_helper_prepare - setup a drm_fb_helper structure
> + * @dev: DRM device
> + * @helper: driver-allocated fbdev helper structure to set up
> + * @funcs: pointer to structure of functions associate with this helper
> + *
> + * Sets up the bare minimum to make the framebuffer helper usable. This is
> + * useful to implement race-free initialization of the polling helpers.
> + */
> +void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
> + const struct drm_fb_helper_funcs *funcs)
> +{
> + INIT_LIST_HEAD(&helper->kernel_fb_list);
> + helper->funcs = funcs;
> + helper->dev = dev;
> +}
> +EXPORT_SYMBOL(drm_fb_helper_prepare);
> +
> +/**
> * drm_fb_helper_init - initialize a drm_fb_helper structure
> * @dev: drm device
> * @fb_helper: driver-allocated fbdev helper structure to initialize
> @@ -513,8 +545,7 @@ static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
> * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
> * to allow driver writes more control over the exact init sequence.
> *
> - * Drivers must set fb_helper->funcs before calling
> - * drm_fb_helper_initial_config().
> + * Drivers must call drm_fb_helper_prepare() before calling this function.
> *
> * RETURNS:
> * Zero if everything went ok, nonzero otherwise.
> @@ -529,10 +560,6 @@ int drm_fb_helper_init(struct drm_device *dev,
> if (!max_conn_count)
> return -EINVAL;
>
> - fb_helper->dev = dev;
> -
> - INIT_LIST_HEAD(&fb_helper->kernel_fb_list);
> -
> fb_helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
> if (!fb_helper->crtc_info)
> return -ENOMEM;
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> index 7ccf04917f47..46443971d517 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> @@ -274,7 +274,8 @@ int exynos_drm_fbdev_init(struct drm_device *dev)
> return -ENOMEM;
>
> private->fb_helper = helper = &fbdev->drm_fb_helper;
> - helper->funcs = &exynos_drm_fb_helper_funcs;
> +
> + drm_fb_helper_prepare(dev, helper, &exynos_drm_fb_helper_funcs);
>
> num_crtc = dev->mode_config.num_crtc;
>
> diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
> index 76e4d777d01d..d0dd3bea8aa5 100644
> --- a/drivers/gpu/drm/gma500/framebuffer.c
> +++ b/drivers/gpu/drm/gma500/framebuffer.c
> @@ -600,7 +600,8 @@ int psb_fbdev_init(struct drm_device *dev)
> }
>
> dev_priv->fbdev = fbdev;
> - fbdev->psb_fb_helper.funcs = &psb_fb_helper_funcs;
> +
> + drm_fb_helper_prepare(dev, &fbdev->psb_fb_helper, &psb_fb_helper_funcs);
>
> drm_fb_helper_init(dev, &fbdev->psb_fb_helper, dev_priv->ops->crtcs,
> INTELFB_CONN_LIMIT);
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> index 336a89f2549e..735890c9ef5a 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -600,7 +600,8 @@ int intel_fbdev_init(struct drm_device *dev)
> if (ifbdev == NULL)
> return -ENOMEM;
>
> - ifbdev->helper.funcs = &intel_fb_helper_funcs;
> + drm_fb_helper_prepare(dev, &ifbdev->helper, &intel_fb_helper_funcs);
> +
> if (!intel_fbdev_init_bios(dev, ifbdev))
> ifbdev->preferred_bpp = 32;
>
> diff --git a/drivers/gpu/drm/mgag200/mgag200_fb.c b/drivers/gpu/drm/mgag200/mgag200_fb.c
> index a4319aba9180..5451dc58eff1 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_fb.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_fb.c
> @@ -293,9 +293,10 @@ int mgag200_fbdev_init(struct mga_device *mdev)
> return -ENOMEM;
>
> mdev->mfbdev = mfbdev;
> - mfbdev->helper.funcs = &mga_fb_helper_funcs;
> spin_lock_init(&mfbdev->dirty_lock);
>
> + drm_fb_helper_prepare(mdev->dev, &mfbdev->helper, &mga_fb_helper_funcs);
> +
> ret = drm_fb_helper_init(mdev->dev, &mfbdev->helper,
> mdev->num_crtc, MGAG200FB_CONN_LIMIT);
> if (ret)
> diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
> index 841665862f2f..745b1be4acf0 100644
> --- a/drivers/gpu/drm/msm/msm_fbdev.c
> +++ b/drivers/gpu/drm/msm/msm_fbdev.c
> @@ -200,7 +200,7 @@ struct drm_fb_helper *msm_fbdev_init(struct drm_device *dev)
>
> helper = &fbdev->base;
>
> - helper->funcs = &msm_fb_helper_funcs;
> + drm_fb_helper_prepare(dev, helper, &msm_fb_helper_funcs);
>
> ret = drm_fb_helper_init(dev, helper,
> priv->num_crtcs, priv->num_connectors);
> diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
> index 8e9c07b7fc89..afe706a20f97 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
> @@ -464,7 +464,8 @@ nouveau_fbcon_init(struct drm_device *dev)
>
> fbcon->dev = dev;
> drm->fbcon = fbcon;
> - fbcon->helper.funcs = &nouveau_fbcon_helper_funcs;
> +
> + drm_fb_helper_prepare(dev, &fbcon->helper, &nouveau_fbcon_helper_funcs);
>
> ret = drm_fb_helper_init(dev, &fbcon->helper,
> dev->mode_config.num_crtc, 4);
> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> index 4cb12083eb12..8436c6857cda 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> @@ -325,7 +325,7 @@ struct drm_fb_helper *omap_fbdev_init(struct drm_device *dev)
>
> helper = &fbdev->base;
>
> - helper->funcs = &omap_fb_helper_funcs;
> + drm_fb_helper_prepare(dev, helper, &omap_fb_helper_funcs);
>
> ret = drm_fb_helper_init(dev, helper,
> priv->num_crtcs, priv->num_connectors);
> diff --git a/drivers/gpu/drm/qxl/qxl_fb.c b/drivers/gpu/drm/qxl/qxl_fb.c
> index cf89614c72be..df567888bb1e 100644
> --- a/drivers/gpu/drm/qxl/qxl_fb.c
> +++ b/drivers/gpu/drm/qxl/qxl_fb.c
> @@ -676,9 +676,12 @@ int qxl_fbdev_init(struct qxl_device *qdev)
>
> qfbdev->qdev = qdev;
> qdev->mode_info.qfbdev = qfbdev;
> - qfbdev->helper.funcs = &qxl_fb_helper_funcs;
> spin_lock_init(&qfbdev->delayed_ops_lock);
> INIT_LIST_HEAD(&qfbdev->delayed_ops);
> +
> + drm_fb_helper_prepare(qdev->ddev, &qfbdev->helper,
> + &qxl_fb_helper_funcs);
> +
> ret = drm_fb_helper_init(qdev->ddev, &qfbdev->helper,
> qxl_num_crtc /* num_crtc - QXL supports just 1 */,
> QXLFB_CONN_LIMIT);
> diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
> index ad97afdbc4c7..db598d712901 100644
> --- a/drivers/gpu/drm/radeon/radeon_fb.c
> +++ b/drivers/gpu/drm/radeon/radeon_fb.c
> @@ -353,7 +353,9 @@ int radeon_fbdev_init(struct radeon_device *rdev)
>
> rfbdev->rdev = rdev;
> rdev->mode_info.rfbdev = rfbdev;
> - rfbdev->helper.funcs = &radeon_fb_helper_funcs;
> +
> + drm_fb_helper_prepare(rdev->ddev, &rfbdev->helper,
> + &radeon_fb_helper_funcs);
>
> ret = drm_fb_helper_init(rdev->ddev, &rfbdev->helper,
> rdev->num_crtc,
> diff --git a/drivers/gpu/drm/tegra/fb.c b/drivers/gpu/drm/tegra/fb.c
> index 75bed72a9755..2e3758542c89 100644
> --- a/drivers/gpu/drm/tegra/fb.c
> +++ b/drivers/gpu/drm/tegra/fb.c
> @@ -276,7 +276,6 @@ static struct tegra_fbdev *tegra_fbdev_create(struct drm_device *drm,
> unsigned int num_crtc,
> unsigned int max_connectors)
> {
> - struct drm_fb_helper *helper;
> struct tegra_fbdev *fbdev;
> int err;
>
> @@ -286,8 +285,7 @@ static struct tegra_fbdev *tegra_fbdev_create(struct drm_device *drm,
> return ERR_PTR(-ENOMEM);
> }
>
> - fbdev->base.funcs = &tegra_fb_helper_funcs;
> - helper = &fbdev->base;
> + drm_fb_helper_prepare(drm, &fbdev->base, &tegra_fb_helper_funcs);
>
> err = drm_fb_helper_init(drm, &fbdev->base, num_crtc, max_connectors);
> if (err < 0) {
> diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c
> index 0647c8cc368b..d1da339843ca 100644
> --- a/drivers/gpu/drm/udl/udl_fb.c
> +++ b/drivers/gpu/drm/udl/udl_fb.c
> @@ -583,7 +583,8 @@ int udl_fbdev_init(struct drm_device *dev)
> return -ENOMEM;
>
> udl->fbdev = ufbdev;
> - ufbdev->helper.funcs = &udl_fb_helper_funcs;
> +
> + drm_fb_helper_prepare(dev, &ufbdev->helper, &udl_fb_helper_funcs);
>
> ret = drm_fb_helper_init(dev, &ufbdev->helper,
> 1, 1);
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index e8c8eeb3a253..9b83c66a5f13 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -97,6 +97,8 @@ struct drm_fb_helper {
> bool delayed_hotplug;
> };
>
> +void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
> + const struct drm_fb_helper_funcs *funcs);
> int drm_fb_helper_init(struct drm_device *dev,
> struct drm_fb_helper *helper, int crtc_count,
> int max_conn);
> --
> 1.9.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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