Merge tag 'topic/drm-misc-2016-07-28' of git://anongit.freedesktop.org/drm-intel into drm-next

A few more simple fixes that Sean&I collected. There's a bunch of bigger
things on dri-devel, but I think those are all too late for 4.8 really.
I'll try and go collect them after -rc1 for 4.9.

* tag 'topic/drm-misc-2016-07-28' of git://anongit.freedesktop.org/drm-intel:
  drm/arm: mali-dp: Fix error return code in malidp_bind()
  drm/arm: mali-dp: Remove redundant dev_err call in malidp_bind()
  drm/gma500: remove unnecessary stub for fb_ioctl()
  apple-gmux: Sphinxify docs
  drm/arm: mali-dp: Set crtc.port to the port instead of the endpoint
  drm/sti: use new Reset API
  drm/etnaviv: Optimize error handling in etnaviv_gem_new_userptr()
  drm/etnaviv: Delete unnecessary checks before two function calls
  drm/vmwgfx: Delete an unnecessary check before the function call "vfree"
  drm/qxl: Delete an unnecessary check before drm_gem_object_unreference_unlocked()
  drm/mgag200: Delete an unnecessary check before drm_gem_object_unreference_unlocked()
  drm/bridge: ps8622: Delete an unnecessary check before backlight_device_unregister()
  GPU-DRM-GMA500: Delete unnecessary checks before two function calls
  GPU-DRM-OMAP: Delete unnecessary checks before two function calls

15 files changed, 66 insertions, 86 deletions

diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index e5b44e92f8cf..82171d223f2d 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -257,6 +257,7 @@ static int malidp_bind(struct device *dev)
 {
 	struct resource *res;
 	struct drm_device *drm;
+	struct device_node *ep;
 	struct malidp_drm *malidp;
 	struct malidp_hw_device *hwdev;
 	struct platform_device *pdev = to_platform_device(dev);
@@ -284,10 +285,8 @@ static int malidp_bind(struct device *dev)
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	hwdev->regs = devm_ioremap_resource(dev, res);
-	if (IS_ERR(hwdev->regs)) {
-		DRM_ERROR("Failed to map control registers area\n");
+	if (IS_ERR(hwdev->regs))
 		return PTR_ERR(hwdev->regs);
-	}
 
 	hwdev->pclk = devm_clk_get(dev, "pclk");
 	if (IS_ERR(hwdev->pclk))
@@ -360,11 +359,14 @@ static int malidp_bind(struct device *dev)
 		goto register_fail;
 
 	/* Set the CRTC's port so that the encoder component can find it */
-	malidp->crtc.port = of_graph_get_next_endpoint(dev->of_node, NULL);
+	ep = of_graph_get_next_endpoint(dev->of_node, NULL);
+	if (!ep) {
+		ret = -EINVAL;
+		goto port_fail;
+	}
+	malidp->crtc.port = of_get_next_parent(ep);
 
 	ret = component_bind_all(dev, drm);
-	of_node_put(malidp->crtc.port);
-
 	if (ret) {
 		DRM_ERROR("Failed to bind all components\n");
 		goto bind_fail;
@@ -402,6 +404,9 @@ vblank_fail:
 irq_init_fail:
 	component_unbind_all(dev, drm);
 bind_fail:
+	of_node_put(malidp->crtc.port);
+	malidp->crtc.port = NULL;
+port_fail:
 	drm_dev_unregister(drm);
 register_fail:
 	malidp_de_planes_destroy(drm);
@@ -435,6 +440,8 @@ static void malidp_unbind(struct device *dev)
 	malidp_de_irq_fini(drm);
 	drm_vblank_cleanup(drm);
 	component_unbind_all(dev, drm);
+	of_node_put(malidp->crtc.port);
+	malidp->crtc.port = NULL;
 	drm_dev_unregister(drm);
 	malidp_de_planes_destroy(drm);
 	drm_mode_config_cleanup(drm);
diff --git a/drivers/gpu/drm/bridge/parade-ps8622.c b/drivers/gpu/drm/bridge/parade-ps8622.c
index 5cd8dd7e5904..583b8ce614e3 100644
--- a/drivers/gpu/drm/bridge/parade-ps8622.c
+++ b/drivers/gpu/drm/bridge/parade-ps8622.c
@@ -636,9 +636,7 @@ static int ps8622_remove(struct i2c_client *client)
 {
 	struct ps8622_bridge *ps8622 = i2c_get_clientdata(client);
 
-	if (ps8622->bl)
-		backlight_device_unregister(ps8622->bl);
-
+	backlight_device_unregister(ps8622->bl);
 	drm_bridge_remove(&ps8622->bridge);
 
 	return 0;
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index df9bcbab922f..56fb8637bb57 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -535,8 +535,7 @@ void etnaviv_gem_describe_objects(struct etnaviv_drm_private *priv,
 
 static void etnaviv_gem_shmem_release(struct etnaviv_gem_object *etnaviv_obj)
 {
-	if (etnaviv_obj->vaddr)
-		vunmap(etnaviv_obj->vaddr);
+	vunmap(etnaviv_obj->vaddr);
 	put_pages(etnaviv_obj);
 }
 
@@ -670,9 +669,7 @@ static struct drm_gem_object *__etnaviv_gem_new(struct drm_device *dev,
 	return obj;
 
 fail:
-	if (obj)
-		drm_gem_object_unreference_unlocked(obj);
-
+	drm_gem_object_unreference_unlocked(obj);
 	return ERR_PTR(ret);
 }
 
@@ -916,15 +913,12 @@ int etnaviv_gem_new_userptr(struct drm_device *dev, struct drm_file *file,
 	get_task_struct(current);
 
 	ret = etnaviv_gem_obj_add(dev, &etnaviv_obj->base);
-	if (ret) {
-		drm_gem_object_unreference_unlocked(&etnaviv_obj->base);
-		return ret;
-	}
+	if (ret)
+		goto unreference;
 
 	ret = drm_gem_handle_create(file, &etnaviv_obj->base, handle);
-
+unreference:
 	/* drop reference from allocate - handle holds it now */
 	drm_gem_object_unreference_unlocked(&etnaviv_obj->base);
-
 	return ret;
 }
diff --git a/drivers/gpu/drm/gma500/cdv_intel_hdmi.c b/drivers/gpu/drm/gma500/cdv_intel_hdmi.c
index 28f9d90988ff..563f193fcfac 100644
--- a/drivers/gpu/drm/gma500/cdv_intel_hdmi.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_hdmi.c
@@ -246,8 +246,7 @@ static void cdv_hdmi_destroy(struct drm_connector *connector)
 {
 	struct gma_encoder *gma_encoder = gma_attached_encoder(connector);
 
-	if (gma_encoder->i2c_bus)
-		psb_intel_i2c_destroy(gma_encoder->i2c_bus);
+	psb_intel_i2c_destroy(gma_encoder->i2c_bus);
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
 	kfree(connector);
diff --git a/drivers/gpu/drm/gma500/cdv_intel_lvds.c b/drivers/gpu/drm/gma500/cdv_intel_lvds.c
index 813ef23a8054..38dc89083148 100644
--- a/drivers/gpu/drm/gma500/cdv_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_lvds.c
@@ -444,8 +444,7 @@ static void cdv_intel_lvds_destroy(struct drm_connector *connector)
 {
 	struct gma_encoder *gma_encoder = gma_attached_encoder(connector);
 
-	if (gma_encoder->i2c_bus)
-		psb_intel_i2c_destroy(gma_encoder->i2c_bus);
+	psb_intel_i2c_destroy(gma_encoder->i2c_bus);
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
 	kfree(connector);
@@ -780,12 +779,10 @@ out:
 failed_find:
 	mutex_unlock(&dev->mode_config.mutex);
 	printk(KERN_ERR "Failed find\n");
-	if (gma_encoder->ddc_bus)
-		psb_intel_i2c_destroy(gma_encoder->ddc_bus);
+	psb_intel_i2c_destroy(gma_encoder->ddc_bus);
 failed_ddc:
 	printk(KERN_ERR "Failed DDC\n");
-	if (gma_encoder->i2c_bus)
-		psb_intel_i2c_destroy(gma_encoder->i2c_bus);
+	psb_intel_i2c_destroy(gma_encoder->i2c_bus);
 failed_blc_i2c:
 	printk(KERN_ERR "Failed BLC\n");
 	drm_encoder_cleanup(encoder);
diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index 7440bf90ac9c..0fcdce0817de 100644
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -184,12 +184,6 @@ static int psbfb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	return 0;
 }
 
-static int psbfb_ioctl(struct fb_info *info, unsigned int cmd,
-						unsigned long arg)
-{
-	return -ENOTTY;
-}
-
 static struct fb_ops psbfb_ops = {
 	.owner = THIS_MODULE,
 	.fb_check_var = drm_fb_helper_check_var,
@@ -201,7 +195,6 @@ static struct fb_ops psbfb_ops = {
 	.fb_imageblit = drm_fb_helper_cfb_imageblit,
 	.fb_mmap = psbfb_mmap,
 	.fb_sync = psbfb_sync,
-	.fb_ioctl = psbfb_ioctl,
 };
 
 static struct fb_ops psbfb_roll_ops = {
@@ -215,7 +208,6 @@ static struct fb_ops psbfb_roll_ops = {
 	.fb_imageblit = drm_fb_helper_cfb_imageblit,
 	.fb_pan_display = psbfb_pan,
 	.fb_mmap = psbfb_mmap,
-	.fb_ioctl = psbfb_ioctl,
 };
 
 static struct fb_ops psbfb_unaccel_ops = {
@@ -228,7 +220,6 @@ static struct fb_ops psbfb_unaccel_ops = {
 	.fb_copyarea = drm_fb_helper_cfb_copyarea,
 	.fb_imageblit = drm_fb_helper_cfb_imageblit,
 	.fb_mmap = psbfb_mmap,
-	.fb_ioctl = psbfb_ioctl,
 };
 
 /**
diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c
index 82b8ce418b27..50eb944fb78a 100644
--- a/drivers/gpu/drm/gma500/psb_drv.c
+++ b/drivers/gpu/drm/gma500/psb_drv.c
@@ -210,10 +210,8 @@ static int psb_driver_unload(struct drm_device *dev)
 			iounmap(dev_priv->aux_reg);
 			dev_priv->aux_reg = NULL;
 		}
-		if (dev_priv->aux_pdev)
-			pci_dev_put(dev_priv->aux_pdev);
-		if (dev_priv->lpc_pdev)
-			pci_dev_put(dev_priv->lpc_pdev);
+		pci_dev_put(dev_priv->aux_pdev);
+		pci_dev_put(dev_priv->lpc_pdev);
 
 		/* Destroy VBT data */
 		psb_intel_destroy_bios(dev);
diff --git a/drivers/gpu/drm/gma500/psb_intel_lvds.c b/drivers/gpu/drm/gma500/psb_intel_lvds.c
index b1b93317d054..e55733ca46d2 100644
--- a/drivers/gpu/drm/gma500/psb_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/psb_intel_lvds.c
@@ -561,8 +561,7 @@ void psb_intel_lvds_destroy(struct drm_connector *connector)
 	struct gma_encoder *gma_encoder = gma_attached_encoder(connector);
 	struct psb_intel_lvds_priv *lvds_priv = gma_encoder->dev_priv;
 
-	if (lvds_priv->ddc_bus)
-		psb_intel_i2c_destroy(lvds_priv->ddc_bus);
+	psb_intel_i2c_destroy(lvds_priv->ddc_bus);
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
 	kfree(connector);
@@ -835,11 +834,9 @@ out:
 
 failed_find:
 	mutex_unlock(&dev->mode_config.mutex);
-	if (lvds_priv->ddc_bus)
-		psb_intel_i2c_destroy(lvds_priv->ddc_bus);
+	psb_intel_i2c_destroy(lvds_priv->ddc_bus);
 failed_ddc:
-	if (lvds_priv->i2c_bus)
-		psb_intel_i2c_destroy(lvds_priv->i2c_bus);
+	psb_intel_i2c_destroy(lvds_priv->i2c_bus);
 failed_blc_i2c:
 	drm_encoder_cleanup(encoder);
 	drm_connector_cleanup(connector);
diff --git a/drivers/gpu/drm/mgag200/mgag200_main.c b/drivers/gpu/drm/mgag200/mgag200_main.c
index 615cbb08ba29..13798b3e6beb 100644
--- a/drivers/gpu/drm/mgag200/mgag200_main.c
+++ b/drivers/gpu/drm/mgag200/mgag200_main.c
@@ -17,8 +17,8 @@
 static void mga_user_framebuffer_destroy(struct drm_framebuffer *fb)
 {
 	struct mga_framebuffer *mga_fb = to_mga_framebuffer(fb);
-	if (mga_fb->obj)
-		drm_gem_object_unreference_unlocked(mga_fb->obj);
+
+	drm_gem_object_unreference_unlocked(mga_fb->obj);
 	drm_framebuffer_cleanup(fb);
 	kfree(fb);
 }
diff --git a/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c b/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c
index 1b0cf2d8224b..0eae8afaed90 100644
--- a/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c
+++ b/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c
@@ -1284,8 +1284,7 @@ static int dsicm_probe(struct platform_device *pdev)
 	return 0;
 
 err_sysfs_create:
-	if (bldev != NULL)
-		backlight_device_unregister(bldev);
+	backlight_device_unregister(bldev);
 err_bl:
 	destroy_workqueue(ddata->workqueue);
 err_reg:
diff --git a/drivers/gpu/drm/omapdrm/omap_fb.c b/drivers/gpu/drm/omapdrm/omap_fb.c
index 983c8cf2441c..31f5178c22c7 100644
--- a/drivers/gpu/drm/omapdrm/omap_fb.c
+++ b/drivers/gpu/drm/omapdrm/omap_fb.c
@@ -115,8 +115,8 @@ static void omap_framebuffer_destroy(struct drm_framebuffer *fb)
 
 	for (i = 0; i < n; i++) {
 		struct plane *plane = &omap_fb->planes[i];
-		if (plane->bo)
-			drm_gem_object_unreference_unlocked(plane->bo);
+
+		drm_gem_object_unreference_unlocked(plane->bo);
 	}
 
 	kfree(omap_fb);
diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index ad429683fef7..3aef12742a53 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -468,8 +468,7 @@ void qxl_user_framebuffer_destroy(struct drm_framebuffer *fb)
 {
 	struct qxl_framebuffer *qxl_fb = to_qxl_framebuffer(fb);
 
-	if (qxl_fb->obj)
-		drm_gem_object_unreference_unlocked(qxl_fb->obj);
+	drm_gem_object_unreference_unlocked(qxl_fb->obj);
 	drm_framebuffer_cleanup(fb);
 	kfree(qxl_fb);
 }
diff --git a/drivers/gpu/drm/sti/sti_compositor.c b/drivers/gpu/drm/sti/sti_compositor.c
index bd74732ea09b..134201ecc6fd 100644
--- a/drivers/gpu/drm/sti/sti_compositor.c
+++ b/drivers/gpu/drm/sti/sti_compositor.c
@@ -254,12 +254,12 @@ static int sti_compositor_probe(struct platform_device *pdev)
 	}
 
 	/* Get reset resources */
-	compo->rst_main = devm_reset_control_get(dev, "compo-main");
+	compo->rst_main = devm_reset_control_get_shared(dev, "compo-main");
 	/* Take compo main out of reset */
 	if (!IS_ERR(compo->rst_main))
 		reset_control_deassert(compo->rst_main);
 
-	compo->rst_aux = devm_reset_control_get(dev, "compo-aux");
+	compo->rst_aux = devm_reset_control_get_shared(dev, "compo-aux");
 	/* Take compo aux out of reset */
 	if (!IS_ERR(compo->rst_aux))
 		reset_control_deassert(compo->rst_aux);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 1a1a87cbf109..dc5beff2b4aa 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -3625,9 +3625,7 @@ static int vmw_resize_cmd_bounce(struct vmw_sw_context *sw_context,
 				   (sw_context->cmd_bounce_size >> 1));
 	}
 
-	if (sw_context->cmd_bounce != NULL)
-		vfree(sw_context->cmd_bounce);
-
+	vfree(sw_context->cmd_bounce);
 	sw_context->cmd_bounce = vmalloc(sw_context->cmd_bounce_size);
 
 	if (sw_context->cmd_bounce == NULL) {
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 4034d2d4c507..a66be137324c 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -31,19 +31,21 @@
 /**
  * DOC: Overview
  *
- * :1:  http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
- * :2:  http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
- *
  * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
- * A {1}[Lattice XP2] on pre-retinas, a {2}[Renesas R4F2113] on retinas.
+ * A `Lattice XP2`_ on pre-retinas, a `Renesas R4F2113`_ on retinas.
  *
  * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
  * dual GPUs but no built-in display.)
  *
  * gmux is connected to the LPC bus of the southbridge. Its I/O ports are
  * accessed differently depending on the microcontroller: Driver functions
- * to access a pre-retina gmux are infixed `_pio_`, those for a retina gmux
- * are infixed `_index_`.
+ * to access a pre-retina gmux are infixed ``_pio_``, those for a retina gmux
+ * are infixed ``_index_``.
+ *
+ * .. _Lattice XP2:
+ *     http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
+ * .. _Renesas R4F2113:
+ *     http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
  */
 
 struct apple_gmux_data {
@@ -272,15 +274,15 @@ static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
 /**
  * DOC: Backlight control
  *
- * :3:  http://www.ti.com/lit/ds/symlink/lp8543.pdf
- * :4:  http://www.ti.com/lit/ds/symlink/lp8545.pdf
- *
  * On single GPU MacBooks, the PWM signal for the backlight is generated by
  * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
  * to conserve energy. Hence the PWM signal needs to be generated by a separate
  * backlight driver which is controlled by gmux. The earliest generation
- * MBP5 2008/09 uses a {3}[TI LP8543] backlight driver. All newer models
- * use a {4}[TI LP8545].
+ * MBP5 2008/09 uses a `TI LP8543`_ backlight driver. All newer models
+ * use a `TI LP8545`_.
+ *
+ * .. _TI LP8543: http://www.ti.com/lit/ds/symlink/lp8543.pdf
+ * .. _TI LP8545: http://www.ti.com/lit/ds/symlink/lp8545.pdf
  */
 
 static int gmux_get_brightness(struct backlight_device *bd)
@@ -312,28 +314,20 @@ static const struct backlight_ops gmux_bl_ops = {
 /**
  * DOC: Graphics mux
  *
- * :5:  http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
- * :6:  http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
- * :7:  http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
- * :8:  https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
- * :9:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
- * :10: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
- * :11: http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
- *
  * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
  * either of them to the panel. One of the tricks gmux has up its sleeve is
  * to lengthen the blanking interval of its output during a switch to
  * synchronize it with the GPU switched to. This allows for a flicker-free
- * switch that is imperceptible by the user ({5}[US 8,687,007 B2]).
+ * switch that is imperceptible by the user (`US 8,687,007 B2`_).
  *
  * On retinas, muxing is no longer done by gmux itself, but by a separate
  * chip which is controlled by gmux. The chip is triple sourced, it is
- * either an {6}[NXP CBTL06142], {7}[TI HD3SS212] or {8}[Pericom PI3VDP12412].
+ * either an `NXP CBTL06142`_, `TI HD3SS212`_ or `Pericom PI3VDP12412`_.
  * The panel is driven with eDP instead of LVDS since the pixel clock
  * required for retina resolution exceeds LVDS' limits.
  *
  * Pre-retinas are able to switch the panel's DDC pins separately.
- * This is handled by a {9}[TI SN74LV4066A] which is controlled by gmux.
+ * This is handled by a `TI SN74LV4066A`_ which is controlled by gmux.
  * The inactive GPU can thus probe the panel's EDID without switching over
  * the entire panel. Retinas lack this functionality as the chips used for
  * eDP muxing are incapable of switching the AUX channel separately (see
@@ -344,15 +338,15 @@ static const struct backlight_ops gmux_bl_ops = {
  *
  * The external DP port is only fully switchable on the first two unibody
  * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
- * {6}[NXP CBTL06141] which is controlled by gmux. It's the predecessor of the
+ * `NXP CBTL06141`_ which is controlled by gmux. It's the predecessor of the
  * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
  *
  * The following MacBook Pro generations replaced the external DP port with a
  * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
  * connecting it either to the discrete GPU or the Thunderbolt controller.
  * Oddly enough, while the full port is no longer switchable, AUX and HPD
- * are still switchable by way of an {10}[NXP CBTL03062] (on pre-retinas
- * MBP8 2011 and MBP9 2012) or two {11}[TI TS3DS10224] (on retinas) under the
+ * are still switchable by way of an `NXP CBTL03062`_ (on pre-retinas
+ * MBP8 2011 and MBP9 2012) or two `TI TS3DS10224`_ (on retinas) under the
  * control of gmux. Since the integrated GPU is missing the main link,
  * external displays appear to it as phantoms which fail to link-train.
  *
@@ -365,10 +359,19 @@ static const struct backlight_ops gmux_bl_ops = {
  * of this feature.
  *
  * gmux' initial switch state on bootup is user configurable via the EFI
- * variable `gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9` (5th byte,
+ * variable ``gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9`` (5th byte,
  * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
  * switch the panel and the external DP connector and allocates a framebuffer
  * for the selected GPU.
+ *
+ * .. _US 8,687,007 B2: http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
+ * .. _NXP CBTL06141:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
+ * .. _NXP CBTL06142:   http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
+ * .. _TI HD3SS212:     http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
+ * .. _Pericom PI3VDP12412: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
+ * .. _TI SN74LV4066A:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
+ * .. _NXP CBTL03062:   http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
+ * .. _TI TS3DS10224:   http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
  */
 
 static void gmux_read_switch_state(struct apple_gmux_data *gmux_data)