| Message ID | 20201204220139.15272-6-laurent.pinchart+renesas@ideasonboard.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Kieran Bingham |
| Headers | show |
| Series | drm: rcar-du: Fix LVDS-related crash | expand |
Hi Laurent, On Sat, Dec 05, 2020 at 12:01:35AM +0200, Laurent Pinchart wrote: > devm_kzalloc() is the wrong API to allocate encoders, as the lifetime of > the encoders is tied to the DRM device, not the device to driver > binding. drmm_kzalloc() isn't a good option either, as it would result > in the encoder being freed before being unregistered during the managed > cleanup of the DRM objects. Use a plain kzalloc(), and register a drmm > action to cleanup the encoder. > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> > --- > drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 47 ++++++++++++++--------- > 1 file changed, 29 insertions(+), 18 deletions(-) > > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c > index 0edce24f2053..7c491ff72cd2 100644 > --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c > +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c > @@ -8,12 +8,13 @@ > */ > > #include <linux/export.h> > +#include <linux/slab.h> > > #include <drm/drm_bridge.h> > #include <drm/drm_crtc.h> > +#include <drm/drm_managed.h> > #include <drm/drm_modeset_helper_vtables.h> > #include <drm/drm_panel.h> > -#include <drm/drm_simple_kms_helper.h> > > #include "rcar_du_drv.h" > #include "rcar_du_encoder.h" > @@ -44,6 +45,17 @@ static unsigned int rcar_du_encoder_count_ports(struct device_node *node) > return num_ports; > } > > +static const struct drm_encoder_funcs rcar_du_encoder_funcs = { > +}; > + > +static void rcar_du_encoder_release(struct drm_device *dev, void *res) > +{ > + struct rcar_du_encoder *renc = res; > + > + drm_encoder_cleanup(&renc->base); > + kfree(renc); > +} > + > int rcar_du_encoder_init(struct rcar_du_device *rcdu, > enum rcar_du_output output, > struct device_node *enc_node) > @@ -53,7 +65,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, > struct drm_bridge *bridge; > int ret; > > - renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL); > + renc = kzalloc(sizeof(*renc), GFP_KERNEL); > if (renc == NULL) > return -ENOMEM; > > @@ -76,20 +88,20 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, > > if (IS_ERR(panel)) { > ret = PTR_ERR(panel); > - goto done; > + goto error; > } > > bridge = devm_drm_panel_bridge_add_typed(rcdu->dev, panel, > DRM_MODE_CONNECTOR_DPI); > if (IS_ERR(bridge)) { > ret = PTR_ERR(bridge); > - goto done; > + goto error; > } > } else { > bridge = of_drm_find_bridge(enc_node); > if (!bridge) { > ret = -EPROBE_DEFER; > - goto done; > + goto error; > } > > if (output == RCAR_DU_OUTPUT_LVDS0 || > @@ -104,28 +116,27 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, > if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) { > if (rcar_lvds_dual_link(bridge)) { > ret = -ENOLINK; > - goto done; > + goto error; > } > } > > - ret = drm_simple_encoder_init(rcdu->ddev, encoder, > - DRM_MODE_ENCODER_NONE); > + ret = drm_encoder_init(rcdu->ddev, encoder, &rcar_du_encoder_funcs, > + DRM_MODE_ENCODER_NONE, NULL); I might have missed the reason for this. Why add an action later instead of making rcar_du_encoder_release part of rcar_du_encoder_funcs ? Thanks j > if (ret < 0) > - goto done; > + goto error; > + > + ret = drmm_add_action_or_reset(rcdu->ddev, rcar_du_encoder_release, > + renc); > + if (ret) > + return ret; > > /* > * Attach the bridge to the encoder. The bridge will create the > * connector. > */ > - ret = drm_bridge_attach(encoder, bridge, NULL, 0); > - if (ret) { > - drm_encoder_cleanup(encoder); > - return ret; > - } > - > -done: > - if (ret < 0) > - devm_kfree(rcdu->dev, renc); > + return drm_bridge_attach(encoder, bridge, NULL, 0); > > +error: > + kfree(renc); > return ret; > } > -- > Regards, > > Laurent Pinchart >
Hi Jacopo, On Mon, Dec 14, 2020 at 11:37:50AM +0100, Jacopo Mondi wrote: > On Sat, Dec 05, 2020 at 12:01:35AM +0200, Laurent Pinchart wrote: > > devm_kzalloc() is the wrong API to allocate encoders, as the lifetime of > > the encoders is tied to the DRM device, not the device to driver > > binding. drmm_kzalloc() isn't a good option either, as it would result > > in the encoder being freed before being unregistered during the managed > > cleanup of the DRM objects. Use a plain kzalloc(), and register a drmm > > action to cleanup the encoder. > > > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> > > --- > > drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 47 ++++++++++++++--------- > > 1 file changed, 29 insertions(+), 18 deletions(-) > > > > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c > > index 0edce24f2053..7c491ff72cd2 100644 > > --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c > > +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c > > @@ -8,12 +8,13 @@ > > */ > > > > #include <linux/export.h> > > +#include <linux/slab.h> > > > > #include <drm/drm_bridge.h> > > #include <drm/drm_crtc.h> > > +#include <drm/drm_managed.h> > > #include <drm/drm_modeset_helper_vtables.h> > > #include <drm/drm_panel.h> > > -#include <drm/drm_simple_kms_helper.h> > > > > #include "rcar_du_drv.h" > > #include "rcar_du_encoder.h" > > @@ -44,6 +45,17 @@ static unsigned int rcar_du_encoder_count_ports(struct device_node *node) > > return num_ports; > > } > > > > +static const struct drm_encoder_funcs rcar_du_encoder_funcs = { > > +}; > > + > > +static void rcar_du_encoder_release(struct drm_device *dev, void *res) > > +{ > > + struct rcar_du_encoder *renc = res; > > + > > + drm_encoder_cleanup(&renc->base); > > + kfree(renc); > > +} > > + > > int rcar_du_encoder_init(struct rcar_du_device *rcdu, > > enum rcar_du_output output, > > struct device_node *enc_node) > > @@ -53,7 +65,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, > > struct drm_bridge *bridge; > > int ret; > > > > - renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL); > > + renc = kzalloc(sizeof(*renc), GFP_KERNEL); > > if (renc == NULL) > > return -ENOMEM; > > > > @@ -76,20 +88,20 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, > > > > if (IS_ERR(panel)) { > > ret = PTR_ERR(panel); > > - goto done; > > + goto error; > > } > > > > bridge = devm_drm_panel_bridge_add_typed(rcdu->dev, panel, > > DRM_MODE_CONNECTOR_DPI); > > if (IS_ERR(bridge)) { > > ret = PTR_ERR(bridge); > > - goto done; > > + goto error; > > } > > } else { > > bridge = of_drm_find_bridge(enc_node); > > if (!bridge) { > > ret = -EPROBE_DEFER; > > - goto done; > > + goto error; > > } > > > > if (output == RCAR_DU_OUTPUT_LVDS0 || > > @@ -104,28 +116,27 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, > > if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) { > > if (rcar_lvds_dual_link(bridge)) { > > ret = -ENOLINK; > > - goto done; > > + goto error; > > } > > } > > > > - ret = drm_simple_encoder_init(rcdu->ddev, encoder, > > - DRM_MODE_ENCODER_NONE); > > + ret = drm_encoder_init(rcdu->ddev, encoder, &rcar_du_encoder_funcs, > > + DRM_MODE_ENCODER_NONE, NULL); > > I might have missed the reason for this. > Why add an action later instead of making rcar_du_encoder_release part > of rcar_du_encoder_funcs ? Because the subsystem is moving towards drmm_* instead of manual release callbacks (I don't mind the manual release callbacks personally). Note that there's "[PATCH v4 02/19] drm: add drmm_encoder_alloc()" that should be merged soon, which will allow simplifying this. > > if (ret < 0) > > - goto done; > > + goto error; > > + > > + ret = drmm_add_action_or_reset(rcdu->ddev, rcar_du_encoder_release, > > + renc); > > + if (ret) > > + return ret; > > > > /* > > * Attach the bridge to the encoder. The bridge will create the > > * connector. > > */ > > - ret = drm_bridge_attach(encoder, bridge, NULL, 0); > > - if (ret) { > > - drm_encoder_cleanup(encoder); > > - return ret; > > - } > > - > > -done: > > - if (ret < 0) > > - devm_kfree(rcdu->dev, renc); > > + return drm_bridge_attach(encoder, bridge, NULL, 0); > > > > +error: > > + kfree(renc); > > return ret; > > }
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c index 0edce24f2053..7c491ff72cd2 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c @@ -8,12 +8,13 @@ */ #include <linux/export.h> +#include <linux/slab.h> #include <drm/drm_bridge.h> #include <drm/drm_crtc.h> +#include <drm/drm_managed.h> #include <drm/drm_modeset_helper_vtables.h> #include <drm/drm_panel.h> -#include <drm/drm_simple_kms_helper.h> #include "rcar_du_drv.h" #include "rcar_du_encoder.h" @@ -44,6 +45,17 @@ static unsigned int rcar_du_encoder_count_ports(struct device_node *node) return num_ports; } +static const struct drm_encoder_funcs rcar_du_encoder_funcs = { +}; + +static void rcar_du_encoder_release(struct drm_device *dev, void *res) +{ + struct rcar_du_encoder *renc = res; + + drm_encoder_cleanup(&renc->base); + kfree(renc); +} + int rcar_du_encoder_init(struct rcar_du_device *rcdu, enum rcar_du_output output, struct device_node *enc_node) @@ -53,7 +65,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, struct drm_bridge *bridge; int ret; - renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL); + renc = kzalloc(sizeof(*renc), GFP_KERNEL); if (renc == NULL) return -ENOMEM; @@ -76,20 +88,20 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, if (IS_ERR(panel)) { ret = PTR_ERR(panel); - goto done; + goto error; } bridge = devm_drm_panel_bridge_add_typed(rcdu->dev, panel, DRM_MODE_CONNECTOR_DPI); if (IS_ERR(bridge)) { ret = PTR_ERR(bridge); - goto done; + goto error; } } else { bridge = of_drm_find_bridge(enc_node); if (!bridge) { ret = -EPROBE_DEFER; - goto done; + goto error; } if (output == RCAR_DU_OUTPUT_LVDS0 || @@ -104,28 +116,27 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu, if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) { if (rcar_lvds_dual_link(bridge)) { ret = -ENOLINK; - goto done; + goto error; } } - ret = drm_simple_encoder_init(rcdu->ddev, encoder, - DRM_MODE_ENCODER_NONE); + ret = drm_encoder_init(rcdu->ddev, encoder, &rcar_du_encoder_funcs, + DRM_MODE_ENCODER_NONE, NULL); if (ret < 0) - goto done; + goto error; + + ret = drmm_add_action_or_reset(rcdu->ddev, rcar_du_encoder_release, + renc); + if (ret) + return ret; /* * Attach the bridge to the encoder. The bridge will create the * connector. */ - ret = drm_bridge_attach(encoder, bridge, NULL, 0); - if (ret) { - drm_encoder_cleanup(encoder); - return ret; - } - -done: - if (ret < 0) - devm_kfree(rcdu->dev, renc); + return drm_bridge_attach(encoder, bridge, NULL, 0); +error: + kfree(renc); return ret; }
devm_kzalloc() is the wrong API to allocate encoders, as the lifetime of the encoders is tied to the DRM device, not the device to driver binding. drmm_kzalloc() isn't a good option either, as it would result in the encoder being freed before being unregistered during the managed cleanup of the DRM objects. Use a plain kzalloc(), and register a drmm action to cleanup the encoder. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> --- drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 47 ++++++++++++++--------- 1 file changed, 29 insertions(+), 18 deletions(-)