drm/fh-helper: Split fbdev single-probe helper

Split the single-probe helper's implementation into multiple
functions and get locking and overallocation out of the way of
the surface setup. Simplifies later changes to the setup code.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230102112927.26565-11-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index b3a731b..af14953 100644 (file)
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1726,36 +1726,30 @@ unlock:
 }
 EXPORT_SYMBOL(drm_fb_helper_pan_display);
 
-/*
- * Allocates the backing storage and sets up the fbdev info structure through
- * the ->fb_probe callback.
- */
-static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
-                                        int preferred_bpp)
+
+static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper, int preferred_bpp,
+                                     struct drm_fb_helper_surface_size *sizes)
 {
        struct drm_client_dev *client = &fb_helper->client;
        struct drm_device *dev = fb_helper->dev;
-       struct drm_mode_config *config = &dev->mode_config;
-       int ret = 0;
        int crtc_count = 0;
        struct drm_connector_list_iter conn_iter;
-       struct drm_fb_helper_surface_size sizes;
        struct drm_connector *connector;
        struct drm_mode_set *mode_set;
        int best_depth = 0;
 
-       memset(&sizes, 0, sizeof(struct drm_fb_helper_surface_size));
-       sizes.surface_depth = 24;
-       sizes.surface_bpp = 32;
-       sizes.fb_width = (u32)-1;
-       sizes.fb_height = (u32)-1;
+       memset(sizes, 0, sizeof(struct drm_fb_helper_surface_size));
+       sizes->surface_depth = 24;
+       sizes->surface_bpp = 32;
+       sizes->fb_width = (u32)-1;
+       sizes->fb_height = (u32)-1;
 
        /*
         * If driver picks 8 or 16 by default use that for both depth/bpp
         * to begin with
         */
-       if (preferred_bpp != sizes.surface_bpp)
-               sizes.surface_depth = sizes.surface_bpp = preferred_bpp;
+       if (preferred_bpp != sizes->surface_bpp)
+               sizes->surface_depth = sizes->surface_bpp = preferred_bpp;
 
        drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
        drm_client_for_each_connector_iter(connector, &conn_iter) {
@@ -1766,21 +1760,21 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
                if (cmdline_mode->bpp_specified) {
                        switch (cmdline_mode->bpp) {
                        case 8:
-                               sizes.surface_depth = sizes.surface_bpp = 8;
+                               sizes->surface_depth = sizes->surface_bpp = 8;
                                break;
                        case 15:
-                               sizes.surface_depth = 15;
-                               sizes.surface_bpp = 16;
+                               sizes->surface_depth = 15;
+                               sizes->surface_bpp = 16;
                                break;
                        case 16:
-                               sizes.surface_depth = sizes.surface_bpp = 16;
+                               sizes->surface_depth = sizes->surface_bpp = 16;
                                break;
                        case 24:
-                               sizes.surface_depth = sizes.surface_bpp = 24;
+                               sizes->surface_depth = sizes->surface_bpp = 24;
                                break;
                        case 32:
-                               sizes.surface_depth = 24;
-                               sizes.surface_bpp = 32;
+                               sizes->surface_depth = 24;
+                               sizes->surface_bpp = 32;
                                break;
                        }
                        break;
@@ -1793,7 +1787,6 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
         * supports RGBA5551 (16 bpp, depth 15) but not RGB565 (16 bpp, depth
         * 16) we need to scale down the depth of the sizes we request.
         */
-       mutex_lock(&client->modeset_mutex);
        drm_client_for_each_modeset(mode_set, client) {
                struct drm_crtc *crtc = mode_set->crtc;
                struct drm_plane *plane = crtc->primary;
@@ -1817,13 +1810,13 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
                                continue;
 
                        /* We found a perfect fit, great */
-                       if (fmt->depth == sizes.surface_depth) {
+                       if (fmt->depth == sizes->surface_depth) {
                                best_depth = fmt->depth;
                                break;
                        }
 
                        /* Skip depths above what we're looking for */
-                       if (fmt->depth > sizes.surface_depth)
+                       if (fmt->depth > sizes->surface_depth)
                                continue;
 
                        /* Best depth found so far */
@@ -1831,10 +1824,10 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
                                best_depth = fmt->depth;
                }
        }
-       if (sizes.surface_depth != best_depth && best_depth) {
+       if (sizes->surface_depth != best_depth && best_depth) {
                drm_info(dev, "requested bpp %d, scaled depth down to %d",
-                        sizes.surface_bpp, best_depth);
-               sizes.surface_depth = best_depth;
+                        sizes->surface_bpp, best_depth);
+               sizes->surface_depth = best_depth;
        }
 
        /* first up get a count of crtcs now in use and new min/maxes width/heights */
@@ -1858,8 +1851,10 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
                x = mode_set->x;
                y = mode_set->y;
 
-               sizes.surface_width  = max_t(u32, desired_mode->hdisplay + x, sizes.surface_width);
-               sizes.surface_height = max_t(u32, desired_mode->vdisplay + y, sizes.surface_height);
+               sizes->surface_width  =
+                       max_t(u32, desired_mode->hdisplay + x, sizes->surface_width);
+               sizes->surface_height =
+                       max_t(u32, desired_mode->vdisplay + y, sizes->surface_height);
 
                for (j = 0; j < mode_set->num_connectors; j++) {
                        struct drm_connector *connector = mode_set->connectors[j];
@@ -1875,28 +1870,63 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
                }
 
                if (lasth)
-                       sizes.fb_width  = min_t(u32, desired_mode->hdisplay + x, sizes.fb_width);
+                       sizes->fb_width  = min_t(u32, desired_mode->hdisplay + x, sizes->fb_width);
                if (lastv)
-                       sizes.fb_height = min_t(u32, desired_mode->vdisplay + y, sizes.fb_height);
+                       sizes->fb_height = min_t(u32, desired_mode->vdisplay + y, sizes->fb_height);
        }
-       mutex_unlock(&client->modeset_mutex);
 
-       if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
+       if (crtc_count == 0 || sizes->fb_width == -1 || sizes->fb_height == -1) {
                drm_info(dev, "Cannot find any crtc or sizes\n");
-
-               /* First time: disable all crtc's.. */
-               if (!fb_helper->deferred_setup)
-                       drm_client_modeset_commit(client);
                return -EAGAIN;
        }
 
+       return 0;
+}
+
+static int drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper, int preferred_bpp,
+                                   struct drm_fb_helper_surface_size *sizes)
+{
+       struct drm_client_dev *client = &fb_helper->client;
+       struct drm_device *dev = fb_helper->dev;
+       struct drm_mode_config *config = &dev->mode_config;
+       int ret;
+
+       mutex_lock(&client->modeset_mutex);
+       ret = __drm_fb_helper_find_sizes(fb_helper, preferred_bpp, sizes);
+       mutex_unlock(&client->modeset_mutex);
+
+       if (ret)
+               return ret;
+
        /* Handle our overallocation */
-       sizes.surface_height *= drm_fbdev_overalloc;
-       sizes.surface_height /= 100;
-       if (sizes.surface_height > config->max_height) {
+       sizes->surface_height *= drm_fbdev_overalloc;
+       sizes->surface_height /= 100;
+       if (sizes->surface_height > config->max_height) {
                drm_dbg_kms(dev, "Fbdev over-allocation too large; clamping height to %d\n",
                            config->max_height);
-               sizes.surface_height = config->max_height;
+               sizes->surface_height = config->max_height;
+       }
+
+       return 0;
+}
+
+/*
+ * Allocates the backing storage and sets up the fbdev info structure through
+ * the ->fb_probe callback.
+ */
+static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
+                                        int preferred_bpp)
+{
+       struct drm_client_dev *client = &fb_helper->client;
+       struct drm_fb_helper_surface_size sizes;
+       int ret;
+
+       ret = drm_fb_helper_find_sizes(fb_helper, preferred_bpp, &sizes);
+       if (ret) {
+               /* First time: disable all crtc's.. */
+               if (!fb_helper->deferred_setup)
+                       drm_client_modeset_commit(client);
+               return ret;
        }
 
 #if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)