Hi
Am 19.08.24 um 10:52 schrieb Sui Jingfeng:
Hi, Thomas
I love your patch, yet ...
On 2024/8/16 20:23, Thomas Zimmermann wrote:
i915's fbdev contains additional code for hotplugging a display that
cannot be ported to the common fbdev client. Introduce the callback
struct drm_fb_helper.fb_hotplug and implement it for i915. The fbdev
helpers invoke the callback before handing the hotplug event.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tursulin@xxxxxxxxxxx>
Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Cc: "Thomas Hellström" <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 6 +++
drivers/gpu/drm/i915/display/intel_fbdev.c | 43 ++++++++++++----------
include/drm/drm_fb_helper.h | 13 +++++++
3 files changed, 42 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c
b/drivers/gpu/drm/drm_fb_helper.c
index d9e539b0fd1a..92926cb02dfb 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1938,6 +1938,12 @@ int drm_fb_helper_hotplug_event(struct
drm_fb_helper *fb_helper)
if (!drm_fbdev_emulation || !fb_helper)
return 0;
+ if (fb_helper->funcs->fb_hotplug) {
We seems need to check the existence on the 'fb_helper->funcs' here,
For example:
if (fb_helper->funcs && fb_helper->funcs->fb_hotplug) {
Otherwise, it will de-reference NULL pointer.
Can be observed on a trivial driver though,
with no monitor(display) connected.
Indeed. That needs to be fixed. Thank you for noting.
To give some context: I was hoping to remove drm_fb_helper_funcs at
some point. fb_probe is now gone with these patches and fb_dirty can
certainly be replaced as well. (I once had prototype patches to do
that). This leaves the new callbacks for 915, for which I don't have a
good alternative solution. So it seems that drm_fb_helper_funcs will
only be used by i915/xe in the long term.
Best regards
Thomas
+ err = fb_helper->funcs->fb_hotplug(fb_helper);
+ if (err)
+ return err;
+ }
+
mutex_lock(&fb_helper->lock);
if (fb_helper->deferred_setup) {
err = __drm_fb_helper_initial_config_and_unlock(fb_helper);
diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c
b/drivers/gpu/drm/i915/display/intel_fbdev.c
index c03fb00002a4..abe77ef0bd84 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -305,10 +305,32 @@ static void intelfb_restore(struct
drm_fb_helper *fb_helper)
intel_fbdev_invalidate(ifbdev);
}
+static int intelfb_hotplug(struct drm_fb_helper *fb_helper)
+{
+ struct drm_device *dev = fb_helper->client.dev;
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ struct intel_fbdev *ifbdev = dev_priv->display.fbdev.fbdev;
+ bool send_hpd;
+
+ if (!ifbdev)
+ return -EINVAL;
+
+ mutex_lock(&ifbdev->hpd_lock);
+ send_hpd = !ifbdev->hpd_suspended;
+ ifbdev->hpd_waiting = true;
+ mutex_unlock(&ifbdev->hpd_lock);
+
+ if (!send_hpd || !(ifbdev->vma || dev->fb_helper->deferred_setup))
+ return -EAGAIN;
+
+ return 0;
+}
+
static const struct drm_fb_helper_funcs intel_fb_helper_funcs = {
.fb_probe = intelfb_create,
.fb_dirty = intelfb_dirty,
.fb_restore = intelfb_restore,
+ .fb_hotplug = intelfb_hotplug,
};
/*
@@ -557,25 +579,6 @@ void intel_fbdev_set_suspend(struct drm_device
*dev, int state, bool synchronous
intel_fbdev_hpd_set_suspend(dev_priv, state);
}
-static int intel_fbdev_output_poll_changed(struct drm_device *dev)
-{
- struct intel_fbdev *ifbdev = to_i915(dev)->display.fbdev.fbdev;
- bool send_hpd;
-
- if (!ifbdev)
- return -EINVAL;
-
- mutex_lock(&ifbdev->hpd_lock);
- send_hpd = !ifbdev->hpd_suspended;
- ifbdev->hpd_waiting = true;
- mutex_unlock(&ifbdev->hpd_lock);
-
- if (send_hpd && (ifbdev->vma || dev->fb_helper->deferred_setup))
- drm_fb_helper_hotplug_event(dev->fb_helper);
-
- return 0;
-}
-
static int intel_fbdev_restore_mode(struct drm_i915_private *dev_priv)
{
struct intel_fbdev *ifbdev = dev_priv->display.fbdev.fbdev;
@@ -637,7 +640,7 @@ static int intel_fbdev_client_hotplug(struct
drm_client_dev *client)
int ret;
if (dev->fb_helper)
- return intel_fbdev_output_poll_changed(dev);
+ return drm_fb_helper_hotplug_event(fb_helper);
ret = drm_fb_helper_init(dev, fb_helper);
if (ret)
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index 34eb77c18a13..3dcb9a60e408 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -112,6 +112,19 @@ struct drm_fb_helper_funcs {
* TODO: Fix i915 to not require this callback.
*/
void (*fb_restore)(struct drm_fb_helper *helper);
+
+ /**
+ * @fb_hotplug:
+ *
+ * Driver callback to prepare hotplug event. If set, fbdev
+ * emulation will invoke this callback before sending a hotplug
+ * event.
+ *
+ * Only for i915. Do not use in new code.
+ *
+ * TODO: Fix i915 to not require this callback.
+ */
+ int (*fb_hotplug)(struct drm_fb_helper *helper);
};
/**
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
