diff options
| author | Johan Hovold <johan+linaro@kernel.org> | 2022-10-25 10:35:49 +0200 |
|---|---|---|
| committer | Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> | 2023-03-13 16:03:03 +0530 |
| commit | b58ec1257ed2bf2e596bed83eb2002ea83697ccd (patch) | |
| tree | f35f855cf81849cae3b6836117d86e672a2ff1dc | |
| parent | 5681ba11481877f74e57b7536776b6500952855b (diff) | |
hack: drm/probe-helper: fix crash on early hotplug event
The PMIC GLINK altmode driver is broken and can forward notifications
before the DRM driver is ready to receive them. To make things worse,
the DRM subsystem also enables forwarding of these notifications before
things have been fully initialised (this bit appears to have been fixed
in 6.3).
Taken together and depending on timing, this can lead to dropped hotplug
notifications or a NULL-pointer dereference during boot.
Work around the immediate issue and trigger a WARN() until this has been
fixed properly.
Link: https://lore.kernel.org/lkml/Y1efJh11B5UQZ0Tz@hovoldconsulting.com/
Link: https://lore.kernel.org/lkml/Y86vaTQR7INWezyj@hovoldconsulting.com/
Not-signed-off-by: Johan Hovold <johan+linaro@kernel.org>
| -rw-r--r-- | drivers/gpu/drm/drm_probe_helper.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index bcd9611dabfd..6a20def83d5a 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -660,7 +660,9 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev) { /* send a uevent + call fbdev */ drm_sysfs_hotplug_event(dev); - if (dev->mode_config.funcs->output_poll_changed) + + WARN_ON(!dev->mode_config.funcs); + if (dev->mode_config.funcs && dev->mode_config.funcs->output_poll_changed) dev->mode_config.funcs->output_poll_changed(dev); drm_client_dev_hotplug(dev); |