Re: [PATCH 4/5] drm/i915: Wrap the preallocated BIOS framebuffer and preserve for KMS fbcon

Bob Paauwe
2013-11-13T22:04:26Z

On Wed, 13 Nov 2013 10:20:47 -0800
Jesse Barnes <jbarnes@virtuousgeek.org> wrote:

> Retrieve current framebuffer config info from the regs and create an fb
> object for the buffer the BIOS or boot loader left us. This should
> allow for smooth transitions to userspace apps once we finish the
> initial configuration construction.
>
> v2: check for non-native modes and adjust (Jesse)
> fixup aperture and cmap frees (Imre)
> use unlocked unref if init_bios fails (Jesse)
> fix curly brace around DSPADDR check (Imre)
> comment failure path for pin_and_fence (Imre)
> v3: fixup fixup of aperture frees (Chris)
> v4: update to current bits (locking & pin_and_fence hack) (Jesse)
> v5: move fb config fetch to display code (Jesse)
> re-order hw state readout on initial load to suit fb inherit (Jesse)
> re-add pin_and_fence in fbdev code to make sure we refcount properly (Je
> v6: rename to plane_config (Daniel)
> check for valid object when initializing BIOS fb (Jesse)
> split from plane_config readout and other display changes (Jesse)
>
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> ---
> drivers/gpu/drm/i915/i915_drv.c | 5 +
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> drivers/gpu/drm/i915/intel_drv.h | 2 +
> drivers/gpu/drm/i915/intel_fbdev.c | 187 +++++++++++++++++++++++++++++++++++--
> 4 files changed, 189 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 30f4fe7..bcad343 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -154,6 +154,11 @@ module_param_named(prefault_disable, i915_prefault_disable, bool, 0600);
> MODULE_PARM_DESC(prefault_disable,
> "Disable page prefaulting for pread/pwrite/reloc (default:false). For developers only.");
>
> +bool i915_use_bios_fb __read_mostly = 1;
> +module_param_named(use_bios_fb, i915_use_bios_fb, bool, 0600);
> +MODULE_PARM_DESC(use_bios_fb,
> + "Use BIOS allocated framebuffer for fbcon (default: true)");
> +
> static struct drm_driver driver;
> #if IS_ENABLED(CONFIG_AGP_INTEL)
> extern int intel_agp_enabled;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index db6821a..500ccc7 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1877,6 +1877,7 @@ extern bool i915_fastboot __read_mostly;
> extern int i915_enable_pc8 __read_mostly;
> extern int i915_pc8_timeout __read_mostly;
> extern bool i915_prefault_disable __read_mostly;
> +extern bool i915_use_bios_fb __read_mostly;
>
> extern int i915_suspend(struct drm_device *dev, pm_message_t state);
> extern int i915_resume(struct drm_device *dev);
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index cb72304..61dfffd 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -113,6 +113,7 @@ struct intel_fbdev {
> struct intel_framebuffer ifb;
> struct list_head fbdev_list;
> struct drm_display_mode *our_mode;
> + int preferred_bpp;
> };
>
> struct intel_encoder {
> @@ -666,6 +667,7 @@ int intel_framebuffer_init(struct drm_device *dev,
> struct intel_framebuffer *ifb,
> struct drm_mode_fb_cmd2 *mode_cmd,
> struct drm_i915_gem_object *obj);
> +void intel_fbdev_init_bios(struct drm_device *dev);
> void intel_framebuffer_fini(struct intel_framebuffer *fb);
> void intel_prepare_page_flip(struct drm_device *dev, int plane);
> void intel_finish_page_flip(struct drm_device *dev, int pipe);
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> index 8fa946b..adf92dd 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -238,6 +238,69 @@ static void intel_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
> *blue = intel_crtc->lut_b[regno] << 8;
> }
>
> +static struct drm_fb_helper_crtc *
> +intel_fb_helper_crtc(struct drm_fb_helper *fb_helper, struct drm_crtc *crtc)
> +{
> + int i;
> +
> + for (i = 0; i < fb_helper->crtc_count; i++)
> + if (fb_helper->crtc_info[i].mode_set.crtc == crtc)
> + return &fb_helper->crtc_info[i];
> +
> + return NULL;
> +}
> +
> +static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> + struct drm_fb_helper_crtc **crtcs,
> + struct drm_display_mode **modes,
> + bool *enabled, int width, int height)
> +{
> + int i;
> +
> + for (i = 0; i < fb_helper->connector_count; i++) {
> + struct drm_connector *connector;
> + struct drm_encoder *encoder;
> +
> + connector = fb_helper->connector_info[i]->connector;
> + if (!enabled[i]) {
> + DRM_DEBUG_KMS("connector %d not enabled, skipping\n",
> + connector->base.id);
> + continue;
> + }
> +
> + encoder = connector->encoder;
> + if (!encoder || !encoder->crtc) {
> + DRM_DEBUG_KMS("connector %d has no encoder or crtc, skipping\n",
> + connector->base.id);
> + continue;
> + }
> +
> + if (WARN_ON(!encoder->crtc->enabled)) {
> + DRM_DEBUG_KMS("connector %s on crtc %d has inconsistent state, aborting\n",
> + drm_get_connector_name(connector),
> + encoder->crtc->base.id);
> + return false;
> + }
> +
> + if (!to_intel_crtc(encoder->crtc)->active) {
> + DRM_DEBUG_KMS("connector %s on inactive crtc %d, borting\n",
> + drm_get_connector_name(connector),
> + encoder->crtc->base.id);
> + return false;
> + }
> +
> + modes[i] = &encoder->crtc->mode;
> + crtcs[i] = intel_fb_helper_crtc(fb_helper, encoder->crtc);
> +
> + DRM_DEBUG_KMS("connector %s on crtc %d: %s\n",
> + drm_get_connector_name(connector),
> + encoder->crtc->base.id,
> + modes[i]->name);
> + }
> +
> + return true;
> +}
> +
> static struct drm_fb_helper_funcs intel_fb_helper_funcs = {
> .gamma_set = intel_crtc_fb_gamma_set,
> .gamma_get = intel_crtc_fb_gamma_get,
> @@ -264,23 +327,133 @@ static void intel_fbdev_destroy(struct drm_device *dev,
> intel_framebuffer_fini(&ifbdev->ifb);
> }
>
> +/*
> + * Try to read the BIOS display configuration and use it for the initial
> + * fb configuration.
> + *
> + * The BIOS or boot loader will generally create an initial display
> + * configuration for us that includes some set of active pipes and displays.
> + * This routine tries to figure out which pipes are active, what resolutions
> + * are being displayed, and then allocates a framebuffer and initial fb
> + * config based on that data.
> + *
> + * If the BIOS or boot loader leaves the display in VGA mode, there's not
> + * much we can do; switching out of that mode involves allocating a new,
> + * high res buffer, and also recalculating bandwidth requirements for the
> + * new bpp configuration.
> + *
> + * However, if we're loaded into an existing, high res mode, we should
> + * be able to allocate a buffer big enough to handle the largest active
> + * mode, create a mode_set for it, and pass it to the fb helper to create
> + * the configuration.
> + */
> +void intel_fbdev_init_bios(struct drm_device *dev)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + struct intel_fbdev *ifbdev;
> + struct drm_crtc *crtc;
> + struct intel_crtc *intel_crtc;
> + struct intel_plane_config *plane_config;
> + struct drm_mode_fb_cmd2 mode_cmd = { 0 };
> + u32 active = 0;
> +
> + list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> + intel_crtc = to_intel_crtc(crtc);
> +
> + if (!intel_crtc->active) {
> + DRM_DEBUG_KMS("pipe %c not active, skipping\n",
> + pipe_name(intel_crtc->pipe));
> + continue;
> + }
> +
> + active |= 1 << intel_crtc->pipe;
> + break;
> + }
> +
> + plane_config = &intel_crtc->plane_config;
> +
> + if (active == 0 || !plane_config->obj) {
> + DRM_DEBUG_KMS("no active pipes found, not using BIOS config\n");
> + return;
> + }
> +
> + ifbdev = kzalloc(sizeof(struct intel_fbdev), GFP_KERNEL);
> + if (ifbdev == NULL) {
> + DRM_DEBUG_KMS("failed to alloc intel fbdev\n");
> + return;
> + }
> +
> + ifbdev->preferred_bpp = plane_config->bpp;
> + ifbdev->helper.funcs = &intel_fb_helper_funcs;
> + ifbdev->helper.funcs->initial_config = intel_fb_initial_config;
> +
> + mode_cmd.pixel_format = intel_format_to_fourcc(plane_config->pixel_format);
> + mode_cmd.width = plane_config->fb_width;
> + mode_cmd.height = plane_config->fb_height;
> + mode_cmd.pitches[0] = plane_config->pitch;
> +
> + mutex_lock(&dev->struct_mutex);
> +
> + if (intel_framebuffer_init(dev, &ifbdev->ifb, &mode_cmd,
> + plane_config->obj)) {
> + DRM_DEBUG_KMS("intel fb init failed\n");
> + goto out_unref_obj;
> + }
> +
> + /* Assuming a single fb across all pipes here */
> + list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> + if ((active & (1 << to_intel_crtc(crtc)->pipe)) == 0)
> + continue;
> +
> + /*
> + * This should only fail on the first one so we don't need
> + * to cleanup any secondary crtc->fbs
> + */
> + if (intel_pin_and_fence_fb_obj(dev, plane_config->obj, NULL))
> + goto out_unref_obj;
> +
> + crtc->fb = &ifbdev->ifb.base;
> + }
> +
> + dev_priv->fbdev = ifbdev;
> +
> + DRM_DEBUG_KMS("using BIOS fb for initial console\n");
> + mutex_unlock(&dev->struct_mutex);
> + return;
> +
> +out_unref_obj:
> + mutex_unlock(&dev->struct_mutex);
> + drm_gem_object_unreference_unlocked(&plane_config->obj->base);
> + kfree(ifbdev);
> +}
> +
> int intel_fbdev_init(struct drm_device *dev)
> {
> struct intel_fbdev *ifbdev;
> struct drm_i915_private *dev_priv = dev->dev_private;
> int ret;
>
> - ifbdev = kzalloc(sizeof(*ifbdev), GFP_KERNEL);
> - if (!ifbdev)
> - return -ENOMEM;
> + if (i915_use_bios_fb)
> + intel_fbdev_init_bios(dev);
> +
> + if ((ifbdev = dev_priv->fbdev) == NULL) {
> + ifbdev = kzalloc(sizeof(struct intel_fbdev), GFP_KERNEL);
> + if (ifbdev == NULL)
> + return -ENOMEM;
> +
> + ifbdev->helper.funcs = &intel_fb_helper_funcs;
> + ifbdev->preferred_bpp = 32;
> +
> + dev_priv->fbdev = ifbdev;
> + }
>
> - dev_priv->fbdev = ifbdev;
> ifbdev->helper.funcs = &intel_fb_helper_funcs;

Should helper.funcs still be set here? It looks like it will be set by
intel_fbdev_init_bios if that is called/succeeds and otherwise set
a few lines above inside the if. If it is set in intel_fbdev_init_bios
then this will override the change made there to the initial_config
helper.

>
> ret = drm_fb_helper_init(dev, &ifbdev->helper,
> INTEL_INFO(dev)->num_pipes,
> 4);
> if (ret) {
> + dev_priv->fbdev = NULL;
> kfree(ifbdev);
> return ret;
> }
> @@ -293,9 +466,10 @@ int intel_fbdev_init(struct drm_device *dev)
> void intel_fbdev_initial_config(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> + struct intel_fbdev *ifbdev = dev_priv->fbdev;
>
> /* Due to peculiar init order wrt to hpd handling this is separate. */
> - drm_fb_helper_initial_config(&dev_priv->fbdev->helper, 32);
> + drm_fb_helper_initial_config(&ifbdev->helper, ifbdev->preferred_bpp);
> }
>
> void intel_fbdev_fini(struct drm_device *dev)
> @@ -335,7 +509,8 @@ MODULE_LICENSE("GPL and additional rights");
> void intel_fbdev_output_poll_changed(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> - drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
> + if (dev_priv->fbdev)
> + drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
> }
>
> void intel_fbdev_restore_mode(struct drm_device *dev)