[PATCH] drm/udl: Fixed problem with UDL adpater reconnection

Robert Tarasov tutankhamen at chromium.org
Wed Oct 11 20:41:42 UTC 2017


Fixed problem with DisplayLink and DisplayLink certified adapters when they
didn't want to work if they were initialized with disconnected DVI cable. Now
udl driver checks and updates adapter's connection state every 10 seconds, as
well as retreives all the edid data blocks instead of only base one. Previous
approch could lead to improper initialization of video mode with certain
monitors.

Signed-off-by: Robert Tarasov <tutankhamen at chromium.org>
---
 drivers/gpu/drm/udl/udl_connector.c | 153 ++++++++++++++++++++++++------------
 drivers/gpu/drm/udl/udl_connector.h |  13 +++
 drivers/gpu/drm/udl/udl_drv.c       |   4 +
 drivers/gpu/drm/udl/udl_main.c      |   5 ++
 4 files changed, 125 insertions(+), 50 deletions(-)
 create mode 100644 drivers/gpu/drm/udl/udl_connector.h

diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c
index 9f9a49748d17..b2d9ffcc29aa 100644
--- a/drivers/gpu/drm/udl/udl_connector.c
+++ b/drivers/gpu/drm/udl/udl_connector.c
@@ -14,70 +14,95 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_edid.h>
 #include <drm/drm_crtc_helper.h>
+#include "udl_connector.h"
 #include "udl_drv.h"
 
-/* dummy connector to just get EDID,
-   all UDL appear to have a DVI-D */
-
-static u8 *udl_get_edid(struct udl_device *udl)
+static bool udl_get_edid_block(struct udl_device *udl, int block_idx,
+							   u8 *buff)
 {
-	u8 *block;
-	char *rbuf;
 	int ret, i;
+	u8 *read_buff;
 
-	block = kmalloc(EDID_LENGTH, GFP_KERNEL);
-	if (block == NULL)
-		return NULL;
-
-	rbuf = kmalloc(2, GFP_KERNEL);
-	if (rbuf == NULL)
-		goto error;
+	read_buff = kmalloc(2, GFP_KERNEL);
+	if (!read_buff)
+		return false;
 
 	for (i = 0; i < EDID_LENGTH; i++) {
+		int bval = (i + block_idx * EDID_LENGTH) << 8;
 		ret = usb_control_msg(udl->udev,
-				      usb_rcvctrlpipe(udl->udev, 0), (0x02),
-				      (0x80 | (0x02 << 5)), i << 8, 0xA1, rbuf, 2,
-				      HZ);
+				      usb_rcvctrlpipe(udl->udev, 0),
+					  (0x02), (0x80 | (0x02 << 5)), bval,
+					  0xA1, read_buff, 2, HZ);
 		if (ret < 1) {
 			DRM_ERROR("Read EDID byte %d failed err %x\n", i, ret);
-			goto error;
+			kfree(read_buff);
+			return false;
 		}
-		block[i] = rbuf[1];
+		buff[i] = read_buff[1];
 	}
 
-	kfree(rbuf);
-	return block;
-
-error:
-	kfree(block);
-	kfree(rbuf);
-	return NULL;
+	kfree(read_buff);
+	return true;
 }
 
-static int udl_get_modes(struct drm_connector *connector)
+static bool udl_get_edid(struct udl_device *udl, u8 **result_buff,
+			 int *result_buff_size)
 {
-	struct udl_device *udl = connector->dev->dev_private;
-	struct edid *edid;
-	int ret;
-
-	edid = (struct edid *)udl_get_edid(udl);
-	if (!edid) {
-		drm_mode_connector_update_edid_property(connector, NULL);
-		return 0;
+	int i, extensions;
+	u8 *block_buff = NULL, *buff_ptr;
+
+	block_buff = kmalloc(EDID_LENGTH, GFP_KERNEL);
+	if (block_buff == NULL)
+		return false;
+
+	if (udl_get_edid_block(udl, 0, block_buff) &&
+	    memchr_inv(block_buff, 0, EDID_LENGTH)) {
+		extensions = ((struct edid *)block_buff)->extensions;
+		if (extensions > 0) {
+			/* we have to read all extensions one by one */
+			*result_buff_size = EDID_LENGTH * (extensions + 1);
+			*result_buff = kmalloc(*result_buff_size, GFP_KERNEL);
+			buff_ptr = *result_buff;
+			if (buff_ptr == NULL) {
+				kfree(block_buff);
+				return false;
+			}
+			memcpy(buff_ptr, block_buff, EDID_LENGTH);
+			kfree(block_buff);
+			buff_ptr += EDID_LENGTH;
+			for (i = 1; i < extensions; ++i) {
+				if (udl_get_edid_block(udl, i, buff_ptr)) {
+					buff_ptr += EDID_LENGTH;
+				} else {
+					kfree(*result_buff);
+					*result_buff = NULL;
+					return false;
+				}
+			}
+			return true;
+		}
+		/* we have only base edid block */
+		*result_buff = block_buff;
+		*result_buff_size = EDID_LENGTH;
+		return true;
 	}
 
-	/*
-	 * We only read the main block, but if the monitor reports extension
-	 * blocks then the drm edid code expects them to be present, so patch
-	 * the extension count to 0.
-	 */
-	edid->checksum += edid->extensions;
-	edid->extensions = 0;
-
-	drm_mode_connector_update_edid_property(connector, edid);
-	ret = drm_add_edid_modes(connector, edid);
-	kfree(edid);
-	return ret;
+	kfree(block_buff);
+
+	return false;
+}
+
+static int udl_get_modes(struct drm_connector *connector)
+{
+	struct udl_drm_connector *udl_connector =
+					container_of(connector,
+					struct udl_drm_connector,
+					connector);
+
+	drm_mode_connector_update_edid_property(connector, udl_connector->edid);
+	if (udl_connector->edid)
+		return drm_add_edid_modes(connector, udl_connector->edid);
+	return 0;
 }
 
 static int udl_mode_valid(struct drm_connector *connector,
@@ -96,8 +121,25 @@ static int udl_mode_valid(struct drm_connector *connector,
 static enum drm_connector_status
 udl_detect(struct drm_connector *connector, bool force)
 {
-	if (drm_dev_is_unplugged(connector->dev))
+	u8 *edid_buff = NULL;
+	int edid_buff_size = 0;
+	struct udl_device *udl = connector->dev->dev_private;
+	struct udl_drm_connector *udl_connector =
+					container_of(connector,
+					struct udl_drm_connector,
+					connector);
+
+	/* cleanup previous edid */
+	if (udl_connector->edid != NULL) {
+		kfree(udl_connector->edid);
+		udl_connector->edid = NULL;
+	}
+
+	if (!udl_get_edid(udl, &edid_buff, &edid_buff_size))
 		return connector_status_disconnected;
+
+	udl_connector->edid = (struct edid *)edid_buff;
+
 	return connector_status_connected;
 }
 
@@ -117,8 +159,14 @@ static int udl_connector_set_property(struct drm_connector *connector,
 
 static void udl_connector_destroy(struct drm_connector *connector)
 {
+	struct udl_drm_connector *udl_connector =
+					container_of(connector,
+					struct udl_drm_connector,
+					connector);
+
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
+	kfree(udl_connector->edid);
 	kfree(connector);
 }
 
@@ -138,17 +186,22 @@ static const struct drm_connector_funcs udl_connector_funcs = {
 
 int udl_connector_init(struct drm_device *dev, struct drm_encoder *encoder)
 {
+	struct udl_drm_connector *udl_connector;
 	struct drm_connector *connector;
 
-	connector = kzalloc(sizeof(struct drm_connector), GFP_KERNEL);
-	if (!connector)
+	udl_connector = kzalloc(sizeof(struct udl_drm_connector), GFP_KERNEL);
+	if (!udl_connector)
 		return -ENOMEM;
 
-	drm_connector_init(dev, connector, &udl_connector_funcs, DRM_MODE_CONNECTOR_DVII);
+	connector = &udl_connector->connector;
+	drm_connector_init(dev, connector, &udl_connector_funcs,
+			   DRM_MODE_CONNECTOR_DVII);
 	drm_connector_helper_add(connector, &udl_connector_helper_funcs);
 
 	drm_connector_register(connector);
 	drm_mode_connector_attach_encoder(connector, encoder);
+	connector->polled = DRM_CONNECTOR_POLL_HPD |
+		DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/udl/udl_connector.h b/drivers/gpu/drm/udl/udl_connector.h
new file mode 100644
index 000000000000..0fb0db5c4612
--- /dev/null
+++ b/drivers/gpu/drm/udl/udl_connector.h
@@ -0,0 +1,13 @@
+#ifndef __UDL_CONNECTOR_H__
+#define __UDL_CONNECTOR_H__
+
+#include <drm/drm_crtc.h>
+
+struct udl_drm_connector {
+	struct drm_connector connector;
+	/* last udl_detect edid */
+	struct edid *edid;
+};
+
+
+#endif //__UDL_CONNECTOR_H__
diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
index 31421b6b586e..3c45a3064726 100644
--- a/drivers/gpu/drm/udl/udl_drv.c
+++ b/drivers/gpu/drm/udl/udl_drv.c
@@ -14,6 +14,9 @@
 static int udl_usb_suspend(struct usb_interface *interface,
 			   pm_message_t message)
 {
+	struct drm_device *dev = usb_get_intfdata(interface);
+
+	drm_kms_helper_poll_disable(dev);
 	return 0;
 }
 
@@ -21,6 +24,7 @@ static int udl_usb_resume(struct usb_interface *interface)
 {
 	struct drm_device *dev = usb_get_intfdata(interface);
 
+	drm_kms_helper_poll_enable(dev);
 	udl_modeset_restore(dev);
 	return 0;
 }
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 0328b2c7b210..f1ec4528a73e 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -11,6 +11,7 @@
  * more details.
  */
 #include <drm/drmP.h>
+#include <drm/drm_crtc_helper.h>
 #include "udl_drv.h"
 
 /* -BULK_SIZE as per usb-skeleton. Can we get full page and avoid overhead? */
@@ -350,6 +351,8 @@ int udl_driver_load(struct drm_device *dev, unsigned long flags)
 	if (ret)
 		goto err_fb;
 
+	drm_kms_helper_poll_init(dev);
+
 	return 0;
 err_fb:
 	udl_fbdev_cleanup(dev);
@@ -371,6 +374,8 @@ void udl_driver_unload(struct drm_device *dev)
 {
 	struct udl_device *udl = dev->dev_private;
 
+	drm_kms_helper_poll_fini(dev);
+
 	if (udl->urbs.count)
 		udl_free_urb_list(dev);
 
-- 
2.15.0.rc0.271.g36b669edcc-goog



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