[PATCH 2/2] drm/udl: implement usb_driver suspend/resume.

[Haixia Shi]

The usb_driver suspend and resume function pointers must be populated
to prevent forced unbinding of USB interface driver. See usb/core/driver.c:
unbind_no_pm_drivers_interfaces().

Restore mode and damage the entire frame buffer upon resume.

TEST=suspend and resume with the same UDL device connected
TEST=suspend with UDL, unplug UDL and resume
TEST=suspend with UDL, unplug and connect another UDL device then resume

Signed-off-by: Haixia Shi <hshi at chromium.org>
Reviewed-by: Stphane Marchesin <marcheu at chromium.org>
---
 drivers/gpu/drm/udl/udl_drv.c     | 17 +++++++++++++++++
 drivers/gpu/drm/udl/udl_drv.h     |  2 ++
 drivers/gpu/drm/udl/udl_modeset.c | 13 +++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
index 17d34e0..e5dc73b 100644
--- a/drivers/gpu/drm/udl/udl_drv.c
+++ b/drivers/gpu/drm/udl/udl_drv.c
@@ -16,6 +16,21 @@ static int udl_driver_set_busid(struct drm_device *d, struct 
drm_master *m)
        return 0;
 }

+static int udl_usb_suspend(struct usb_interface *interface,
+                          pm_message_t message)
+{
+       return 0;
+}
+
+static int udl_usb_resume(struct usb_interface *interface)
+{
+       struct drm_device *dev = usb_get_intfdata(interface);
+
+       udl_modeset_restore(dev);
+       return 0;
+}
+
+
 static const struct vm_operations_struct udl_gem_vm_ops = {
        .fault = udl_gem_fault,
        .open = drm_gem_vm_open,
@@ -122,6 +137,8 @@ static struct usb_driver udl_driver = {
        .name = "udl",
        .probe = udl_usb_probe,
        .disconnect = udl_usb_disconnect,
+       .suspend = udl_usb_suspend,
+       .resume = udl_usb_resume,
        .id_table = id_table,
 };
 module_usb_driver(udl_driver);
diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index 0b03d34..f338a57 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -52,6 +52,7 @@ struct udl_device {
        struct device *dev;
        struct drm_device *ddev;
        struct usb_device *udev;
+       struct drm_crtc *crtc;

        int sku_pixel_limit;

@@ -87,6 +88,7 @@ struct udl_framebuffer {

 /* modeset */
 int udl_modeset_init(struct drm_device *dev);
+void udl_modeset_restore(struct drm_device *dev);
 void udl_modeset_cleanup(struct drm_device *dev);
 int udl_connector_init(struct drm_device *dev, struct drm_encoder *encoder);

diff --git a/drivers/gpu/drm/udl/udl_modeset.c 
b/drivers/gpu/drm/udl/udl_modeset.c
index 7369512..69d6a4f 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -309,6 +309,8 @@ static int udl_crtc_mode_set(struct drm_crtc *crtc,
        char *wrptr;
        int color_depth = 0;

+       udl->crtc = crtc;
+
        buf = (char *)udl->mode_buf;

        /* for now we just clip 24 -> 16 - if we fix that fix this */
@@ -450,6 +452,17 @@ int udl_modeset_init(struct drm_device *dev)
        return 0;
 }

+void udl_modeset_restore(struct drm_device *dev)
+{
+       struct udl_device *udl = dev->dev_private;
+       struct udl_framebuffer *ufb;
+       if (!udl->crtc || !udl->crtc->primary->fb)
+               return;
+       udl_crtc_commit(udl->crtc);
+       ufb = to_udl_fb(udl->crtc->primary->fb);
+       udl_handle_damage(ufb, 0, 0, ufb->base.width, ufb->base.height);
+}
+
 void udl_modeset_cleanup(struct drm_device *dev)
 {
        drm_mode_config_cleanup(dev);
-- 
2.8.0.rc3.226.g39d4020