Comment # 15 on bug 1204315 from Takashi Iwai

Then maybe we need drm_aperture_remove_conflicting_pci_framebuffers()?  e.g.

--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -626,6 +626,8 @@ static struct drm_display_mode simpledrm_mode(unsigned int
width,
        return mode;
 }

+static struct drm_driver simpledrm_driver;
+
 static struct simpledrm_device *simpledrm_device_create(struct drm_driver
*drv,
                                                        struct platform_device
*pdev)
 {
@@ -714,6 +716,11 @@ static struct simpledrm_device
*simpledrm_device_create(struct drm_driver *drv,
        if (!res)
                return ERR_PTR(-EINVAL);

+       ret = drm_aperture_remove_conflicting_framebuffers(res->start,
resource_size(res),
+                                                          true,
&simpledrm_driver);
+       if (ret)
+               return ERR_PTR(ret);
+
        ret = devm_aperture_acquire_from_firmware(dev, res->start,
resource_size(res));
        if (ret) {
                drm_err(dev, "could not acquire memory range %pr: error %d\n",
res, ret);
~