| Message ID | 20210326203807.105754-3-lyude@redhat.com |
|---|---|
| State | Rejected |
| Headers | show |
| Series | None | expand |
On Fri, Mar 26, 2021 at 04:37:49PM -0400, Lyude Paul wrote: > As pointed out by the documentation for drm_dp_aux_register(), > drm_dp_aux_init() should be used in situations where the AUX channel for a > display driver can potentially be registered before it's respective DRM > driver. This is the case with Tegra, since the DP aux channel exists as a > platform device instead of being a grandchild of the DRM device. > > Since we're about to add a backpointer to a DP AUX channel's respective DRM > device, let's fix this so that we don't potentially allow userspace to use > the AUX channel before we've associated it with it's DRM connector. > > Signed-off-by: Lyude Paul <lyude@redhat.com> > --- > drivers/gpu/drm/tegra/dpaux.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) Acked-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c index 105fb9cdbb3b..ea56c6ec25e4 100644 --- a/drivers/gpu/drm/tegra/dpaux.c +++ b/drivers/gpu/drm/tegra/dpaux.c @@ -534,9 +534,7 @@ static int tegra_dpaux_probe(struct platform_device *pdev) dpaux->aux.transfer = tegra_dpaux_transfer; dpaux->aux.dev = &pdev->dev; - err = drm_dp_aux_register(&dpaux->aux); - if (err < 0) - return err; + drm_dp_aux_init(&dpaux->aux); /* * Assume that by default the DPAUX/I2C pads will be used for HDMI, @@ -589,8 +587,6 @@ static int tegra_dpaux_remove(struct platform_device *pdev) pm_runtime_put_sync(&pdev->dev); pm_runtime_disable(&pdev->dev); - drm_dp_aux_unregister(&dpaux->aux); - mutex_lock(&dpaux_lock); list_del(&dpaux->list); mutex_unlock(&dpaux_lock); @@ -723,6 +719,10 @@ int drm_dp_aux_attach(struct drm_dp_aux *aux, struct tegra_output *output) unsigned long timeout; int err; + err = drm_dp_aux_register(aux); + if (err < 0) + return err; + output->connector.polled = DRM_CONNECTOR_POLL_HPD; dpaux->output = output; @@ -760,6 +760,7 @@ int drm_dp_aux_detach(struct drm_dp_aux *aux) unsigned long timeout; int err; + drm_dp_aux_unregister(aux); disable_irq(dpaux->irq); if (dpaux->output->panel) {
As pointed out by the documentation for drm_dp_aux_register(), drm_dp_aux_init() should be used in situations where the AUX channel for a display driver can potentially be registered before it's respective DRM driver. This is the case with Tegra, since the DP aux channel exists as a platform device instead of being a grandchild of the DRM device. Since we're about to add a backpointer to a DP AUX channel's respective DRM device, let's fix this so that we don't potentially allow userspace to use the AUX channel before we've associated it with it's DRM connector. Signed-off-by: Lyude Paul <lyude@redhat.com> --- drivers/gpu/drm/tegra/dpaux.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)