1 files changed, 106 insertions, 58 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 9214c8b02484..a0663f44e218 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -56,6 +56,25 @@ MODULE_PARM_DESC(drm_fbdev_overalloc,
 		 "Overallocation of the fbdev buffer (%) [default="
 		 __MODULE_STRING(CONFIG_DRM_FBDEV_OVERALLOC) "]");
 
+/*
+ * In order to keep user-space compatibility, we want in certain use-cases
+ * to keep leaking the fbdev physical address to the user-space program
+ * handling the fbdev buffer.
+ * This is a bad habit essentially kept into closed source opengl driver
+ * that should really be moved into open-source upstream projects instead
+ * of using legacy physical addresses in user space to communicate with
+ * other out-of-tree kernel modules.
+ *
+ * This module_param *should* be removed as soon as possible and be
+ * considered as a broken and legacy behaviour from a modern fbdev device.
+ */
+#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
+static bool drm_leak_fbdev_smem = false;
+module_param_unsafe(drm_leak_fbdev_smem, bool, 0600);
+MODULE_PARM_DESC(fbdev_emulation,
+		 "Allow unsafe leaking fbdev physical smem address [default=false]");
+#endif
+
 static LIST_HEAD(kernel_fb_helper_list);
 static DEFINE_MUTEX(kernel_fb_helper_lock);
 
@@ -1602,6 +1621,64 @@ static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
 	       var_1->transp.msb_right == var_2->transp.msb_right;
 }
 
+static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
+					 u8 depth)
+{
+	switch (depth) {
+	case 8:
+		var->red.offset = 0;
+		var->green.offset = 0;
+		var->blue.offset = 0;
+		var->red.length = 8; /* 8bit DAC */
+		var->green.length = 8;
+		var->blue.length = 8;
+		var->transp.offset = 0;
+		var->transp.length = 0;
+		break;
+	case 15:
+		var->red.offset = 10;
+		var->green.offset = 5;
+		var->blue.offset = 0;
+		var->red.length = 5;
+		var->green.length = 5;
+		var->blue.length = 5;
+		var->transp.offset = 15;
+		var->transp.length = 1;
+		break;
+	case 16:
+		var->red.offset = 11;
+		var->green.offset = 5;
+		var->blue.offset = 0;
+		var->red.length = 5;
+		var->green.length = 6;
+		var->blue.length = 5;
+		var->transp.offset = 0;
+		break;
+	case 24:
+		var->red.offset = 16;
+		var->green.offset = 8;
+		var->blue.offset = 0;
+		var->red.length = 8;
+		var->green.length = 8;
+		var->blue.length = 8;
+		var->transp.offset = 0;
+		var->transp.length = 0;
+		break;
+	case 32:
+		var->red.offset = 16;
+		var->green.offset = 8;
+		var->blue.offset = 0;
+		var->red.length = 8;
+		var->green.length = 8;
+		var->blue.length = 8;
+		var->transp.offset = 24;
+		var->transp.length = 8;
+		break;
+	default:
+		break;
+	}
+}
+
 /**
  * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
  * @var: screeninfo to check
@@ -1613,9 +1690,14 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 	struct drm_fb_helper *fb_helper = info->par;
 	struct drm_framebuffer *fb = fb_helper->fb;
 
-	if (var->pixclock != 0 || in_dbg_master())
+	if (in_dbg_master())
 		return -EINVAL;
 
+	if (var->pixclock != 0) {
+		DRM_DEBUG("fbdev emulation doesn't support changing the pixel clock, value of pixclock is ignored\n");
+		var->pixclock = 0;
+	}
+
 	/*
 	 * Changes struct fb_var_screeninfo are currently not pushed back
 	 * to KMS, hence fail if different settings are requested.
@@ -1632,6 +1714,20 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
 	}
 
 	/*
+	 * Workaround for SDL 1.2, which is known to be setting all pixel format
+	 * fields values to zero in some cases. We treat this situation as a
+	 * kind of "use some reasonable autodetected values".
+	 */
+	if (!var->red.offset     && !var->green.offset    &&
+	    !var->blue.offset    && !var->transp.offset   &&
+	    !var->red.length     && !var->green.length    &&
+	    !var->blue.length    && !var->transp.length   &&
+	    !var->red.msb_right  && !var->green.msb_right &&
+	    !var->blue.msb_right && !var->transp.msb_right) {
+		drm_fb_helper_fill_pixel_fmt(var, fb->format->depth);
+	}
+
+	/*
 	 * drm fbdev emulation doesn't support changing the pixel format at all,
 	 * so reject all pixel format changing requests.
 	 */
@@ -1942,59 +2038,7 @@ void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helpe
 	info->var.yoffset = 0;
 	info->var.activate = FB_ACTIVATE_NOW;
 
-	switch (fb->format->depth) {
-	case 8:
-		info->var.red.offset = 0;
-		info->var.green.offset = 0;
-		info->var.blue.offset = 0;
-		info->var.red.length = 8; /* 8bit DAC */
-		info->var.green.length = 8;
-		info->var.blue.length = 8;
-		info->var.transp.offset = 0;
-		info->var.transp.length = 0;
-		break;
-	case 15:
-		info->var.red.offset = 10;
-		info->var.green.offset = 5;
-		info->var.blue.offset = 0;
-		info->var.red.length = 5;
-		info->var.green.length = 5;
-		info->var.blue.length = 5;
-		info->var.transp.offset = 15;
-		info->var.transp.length = 1;
-		break;
-	case 16:
-		info->var.red.offset = 11;
-		info->var.green.offset = 5;
-		info->var.blue.offset = 0;
-		info->var.red.length = 5;
-		info->var.green.length = 6;
-		info->var.blue.length = 5;
-		info->var.transp.offset = 0;
-		break;
-	case 24:
-		info->var.red.offset = 16;
-		info->var.green.offset = 8;
-		info->var.blue.offset = 0;
-		info->var.red.length = 8;
-		info->var.green.length = 8;
-		info->var.blue.length = 8;
-		info->var.transp.offset = 0;
-		info->var.transp.length = 0;
-		break;
-	case 32:
-		info->var.red.offset = 16;
-		info->var.green.offset = 8;
-		info->var.blue.offset = 0;
-		info->var.red.length = 8;
-		info->var.green.length = 8;
-		info->var.blue.length = 8;
-		info->var.transp.offset = 24;
-		info->var.transp.length = 8;
-		break;
-	default:
-		break;
-	}
+	drm_fb_helper_fill_pixel_fmt(&info->var, fb->format->depth);
 
 	info->var.xres = fb_width;
 	info->var.yres = fb_height;
@@ -2833,7 +2877,7 @@ int drm_fb_helper_fbdev_setup(struct drm_device *dev,
 	return 0;
 
 err_drm_fb_helper_fini:
-	drm_fb_helper_fini(fb_helper);
+	drm_fb_helper_fbdev_teardown(dev);
 
 	return ret;
 }
@@ -3041,6 +3085,12 @@ int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper,
 	fbi->screen_size = fb->height * fb->pitches[0];
 	fbi->fix.smem_len = fbi->screen_size;
 	fbi->screen_buffer = buffer->vaddr;
+	/* Shamelessly leak the physical address to user-space */
+#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
+	if (drm_leak_fbdev_smem && fbi->fix.smem_start == 0)
+		fbi->fix.smem_start =
+			page_to_phys(virt_to_page(fbi->screen_buffer));
+#endif
 	strcpy(fbi->fix.id, "DRM emulated");
 
 	drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->format->depth);
@@ -3106,9 +3156,7 @@ static void drm_fbdev_client_unregister(struct drm_client_dev *client)
 
 static int drm_fbdev_client_restore(struct drm_client_dev *client)
 {
-	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
-
-	drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
+	drm_fb_helper_lastclose(client->dev);
 
 	return 0;
 }