| Message ID | 20190808151150.16336-13-boris.brezillon@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: Add support for bus-format negotiation | expand |
Hi Boris, Thank you for the patch. On Thu, Aug 08, 2019 at 05:11:43PM +0200, Boris Brezillon wrote: > So that bridge drivers have a way to check/reject an atomic operation. > The drm_atomic_bridge_chain_check() (which is just a wrapper around > the ->atomic_check() hook) is called in place of > drm_bridge_chain_mode_fixup() (when ->atomic_check() is not implemented, > the core falls back to ->mode_fixup(), so the behavior should stay > the same for existing bridge drivers). > > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> > --- > drivers/gpu/drm/drm_atomic_helper.c | 11 +++--- > drivers/gpu/drm/drm_bridge.c | 59 +++++++++++++++++++++++++++++ > include/drm/drm_bridge.h | 23 +++++++++++ > 3 files changed, 87 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index e76ec9648b6f..3fadde38ead7 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -445,12 +445,11 @@ mode_fixup(struct drm_atomic_state *state) > encoder = new_conn_state->best_encoder; > funcs = encoder->helper_private; > > - ret = drm_bridge_chain_mode_fixup(encoder, > - &new_crtc_state->mode, > - &new_crtc_state->adjusted_mode); > - if (!ret) { > - DRM_DEBUG_ATOMIC("Bridge fixup failed\n"); > - return -EINVAL; > + ret = drm_atomic_bridge_chain_check(encoder, new_crtc_state, > + new_conn_state); > + if (ret) { > + DRM_DEBUG_ATOMIC("Bridge atomic check failed\n"); > + return ret; > } > > if (funcs && funcs->atomic_check) { > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > index 0528ca941855..dcad661daa74 100644 > --- a/drivers/gpu/drm/drm_bridge.c > +++ b/drivers/gpu/drm/drm_bridge.c > @@ -583,6 +583,65 @@ void drm_atomic_bridge_chain_enable(struct drm_encoder *encoder, > } > EXPORT_SYMBOL(drm_atomic_bridge_chain_enable); > > +static int drm_atomic_bridge_check(struct drm_bridge *bridge, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state) > +{ > + if (bridge->funcs->atomic_check) { > + struct drm_bridge_state *bridge_state; > + int ret; > + > + bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state, > + bridge); > + if (WARN_ON(!bridge_state)) > + return -EINVAL; > + > + ret = bridge->funcs->atomic_check(bridge, bridge_state, > + crtc_state, conn_state); > + if (ret) > + return ret; > + } else if (bridge->funcs->mode_fixup) { > + if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode, > + &crtc_state->adjusted_mode)) > + return -EINVAL; > + } > + > + return 0; > +} > + > +/** > + * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain > + * @encoder: encoder object > + * @crtc_state: new CRTC state > + * @conn_state: new connector state > + * > + * Calls &drm_bridge_funcs.atomic_check() (falls back on > + * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain, > + * starting from the last bridge to the first. These are called before calling > + * &drm_encoder_helper_funcs.atomic_check() > + * > + * RETURNS: > + * 0 on success, a negative error code on failure > + */ > +int drm_atomic_bridge_chain_check(struct drm_encoder *encoder, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state) > +{ > + struct drm_bridge *bridge; > + > + list_for_each_entry_reverse(bridge, &encoder->bridge_chain, > + chain_node) { > + int ret; > + > + ret = drm_atomic_bridge_check(bridge, crtc_state, conn_state); > + if (ret) > + return ret; > + } > + > + return 0; > +} > +EXPORT_SYMBOL(drm_atomic_bridge_chain_check); > + > /** > * drm_atomic_helper_init_bridge_state() - Initializes a bridge state > * @bridge this state is referring to > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h > index 9383b4e4b853..5d8fe3709bde 100644 > --- a/include/drm/drm_bridge.h > +++ b/include/drm/drm_bridge.h > @@ -379,6 +379,26 @@ struct drm_bridge_funcs { > */ > void (*atomic_destroy_state)(struct drm_bridge *bridge, > struct drm_bridge_state *state); > + > + /** > + * @atomic_check: > + * > + * This method is responsible for checking bridge state correctness. > + * It can also check the state of the surrounding components in chain > + * to make sure the whole pipeline can work properly. As this is meant to replace .mode_fixup() you should document that here and in the .mode_fixup() operation. There's also the additional question of what parameters can be modified. Is a bridge .atomic_check() allowed to modify the CRTC or connector state ? Of so, what are the restrictions on how those can be modified ? For instance .mode_fixup() can change the pixel clock but isn't allowed to modify the h/v active values. Those restrictions were not clearly documented for .mode_fixup() and have led to grey areas. I don't want to repeat the same mistake for bridges, we need to be very explicit here. In the list of open questions, what if a bridge changes the pixel clock to a value it supports (as .mode_fixup() does), and then the previous bridge in the chain (the next one in traversal order for the drm_atomic_bridge_chain_check() function) also changes the pixel clock, to a value that the current bridge doesn't support ? I think we really need to think about the semantic of this operation. As the goal of your series is to implement configuration of bus formats between bridges, shouldn't a bridge .atomic_check() also receive the state of the next bridge in the chain ? > + * > + * &drm_bridge_funcs.atomic_check() hooks are called in reverse > + * order (from the last to the first bridge). > + * > + * This method is optional. > + * > + * RETURNS: > + * zero if the check passed, a negative error code otherwise. > + */ > + int (*atomic_check)(struct drm_bridge *bridge, > + struct drm_bridge_state *bridge_state, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state); > }; > > /** > @@ -479,6 +499,9 @@ void drm_bridge_chain_mode_set(struct drm_encoder *encoder, > void drm_bridge_chain_pre_enable(struct drm_encoder *encoder); > void drm_bridge_chain_enable(struct drm_encoder *encoder); > > +int drm_atomic_bridge_chain_check(struct drm_encoder *encoder, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state); > void drm_atomic_bridge_chain_disable(struct drm_encoder *encoder, > struct drm_atomic_state *state); > void drm_atomic_bridge_chain_post_disable(struct drm_encoder *encoder,
On Thu, 22 Aug 2019 03:12:07 +0300 Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > Hi Boris, > > Thank you for the patch. > > On Thu, Aug 08, 2019 at 05:11:43PM +0200, Boris Brezillon wrote: > > So that bridge drivers have a way to check/reject an atomic operation. > > The drm_atomic_bridge_chain_check() (which is just a wrapper around > > the ->atomic_check() hook) is called in place of > > drm_bridge_chain_mode_fixup() (when ->atomic_check() is not implemented, > > the core falls back to ->mode_fixup(), so the behavior should stay > > the same for existing bridge drivers). > > > > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> > > --- > > drivers/gpu/drm/drm_atomic_helper.c | 11 +++--- > > drivers/gpu/drm/drm_bridge.c | 59 +++++++++++++++++++++++++++++ > > include/drm/drm_bridge.h | 23 +++++++++++ > > 3 files changed, 87 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > index e76ec9648b6f..3fadde38ead7 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -445,12 +445,11 @@ mode_fixup(struct drm_atomic_state *state) > > encoder = new_conn_state->best_encoder; > > funcs = encoder->helper_private; > > > > - ret = drm_bridge_chain_mode_fixup(encoder, > > - &new_crtc_state->mode, > > - &new_crtc_state->adjusted_mode); > > - if (!ret) { > > - DRM_DEBUG_ATOMIC("Bridge fixup failed\n"); > > - return -EINVAL; > > + ret = drm_atomic_bridge_chain_check(encoder, new_crtc_state, > > + new_conn_state); > > + if (ret) { > > + DRM_DEBUG_ATOMIC("Bridge atomic check failed\n"); > > + return ret; > > } > > > > if (funcs && funcs->atomic_check) { > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > > index 0528ca941855..dcad661daa74 100644 > > --- a/drivers/gpu/drm/drm_bridge.c > > +++ b/drivers/gpu/drm/drm_bridge.c > > @@ -583,6 +583,65 @@ void drm_atomic_bridge_chain_enable(struct drm_encoder *encoder, > > } > > EXPORT_SYMBOL(drm_atomic_bridge_chain_enable); > > > > +static int drm_atomic_bridge_check(struct drm_bridge *bridge, > > + struct drm_crtc_state *crtc_state, > > + struct drm_connector_state *conn_state) > > +{ > > + if (bridge->funcs->atomic_check) { > > + struct drm_bridge_state *bridge_state; > > + int ret; > > + > > + bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state, > > + bridge); > > + if (WARN_ON(!bridge_state)) > > + return -EINVAL; > > + > > + ret = bridge->funcs->atomic_check(bridge, bridge_state, > > + crtc_state, conn_state); > > + if (ret) > > + return ret; > > + } else if (bridge->funcs->mode_fixup) { > > + if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode, > > + &crtc_state->adjusted_mode)) > > + return -EINVAL; > > + } > > + > > + return 0; > > +} > > + > > +/** > > + * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain > > + * @encoder: encoder object > > + * @crtc_state: new CRTC state > > + * @conn_state: new connector state > > + * > > + * Calls &drm_bridge_funcs.atomic_check() (falls back on > > + * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain, > > + * starting from the last bridge to the first. These are called before calling > > + * &drm_encoder_helper_funcs.atomic_check() > > + * > > + * RETURNS: > > + * 0 on success, a negative error code on failure > > + */ > > +int drm_atomic_bridge_chain_check(struct drm_encoder *encoder, > > + struct drm_crtc_state *crtc_state, > > + struct drm_connector_state *conn_state) > > +{ > > + struct drm_bridge *bridge; > > + > > + list_for_each_entry_reverse(bridge, &encoder->bridge_chain, > > + chain_node) { > > + int ret; > > + > > + ret = drm_atomic_bridge_check(bridge, crtc_state, conn_state); > > + if (ret) > > + return ret; > > + } > > + > > + return 0; > > +} > > +EXPORT_SYMBOL(drm_atomic_bridge_chain_check); > > + > > /** > > * drm_atomic_helper_init_bridge_state() - Initializes a bridge state > > * @bridge this state is referring to > > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h > > index 9383b4e4b853..5d8fe3709bde 100644 > > --- a/include/drm/drm_bridge.h > > +++ b/include/drm/drm_bridge.h > > @@ -379,6 +379,26 @@ struct drm_bridge_funcs { > > */ > > void (*atomic_destroy_state)(struct drm_bridge *bridge, > > struct drm_bridge_state *state); > > + > > + /** > > + * @atomic_check: > > + * > > + * This method is responsible for checking bridge state correctness. > > + * It can also check the state of the surrounding components in chain > > + * to make sure the whole pipeline can work properly. > > As this is meant to replace .mode_fixup() you should document that here > and in the .mode_fixup() operation. > > There's also the additional question of what parameters can be modified. > Is a bridge .atomic_check() allowed to modify the CRTC or connector > state ? Of so, what are the restrictions on how those can be modified ? > For instance .mode_fixup() can change the pixel clock but isn't allowed > to modify the h/v active values. Those restrictions were not clearly > documented for .mode_fixup() and have led to grey areas. I don't want to > repeat the same mistake for bridges, we need to be very explicit here. Any recommendation? I didn't face this problem myself, so I'd need inputs from those who did to take a decision. > > In the list of open questions, what if a bridge changes the pixel clock > to a value it supports (as .mode_fixup() does), and then the previous > bridge in the chain (the next one in traversal order for the > drm_atomic_bridge_chain_check() function) also changes the pixel clock, > to a value that the current bridge doesn't support ? I think we really > need to think about the semantic of this operation. Don't we have the exact same problem right now with the ->mode_fixup() hook when bridges are chained? Not sure why it suddenly becomes a priority to clarify that, but if we quickly settle on this new semantic, I'm fine integrating those changes in my patchset. > > As the goal of your series is to implement configuration of bus formats > between bridges, shouldn't a bridge .atomic_check() also receive the > state of the next bridge in the chain ? I thought we had enough arguments passed to the atomic_check() hook and decided to let the driver retrieve the next state. I can pass the next bridge state if you prefer. > > > + * > > + * &drm_bridge_funcs.atomic_check() hooks are called in reverse > > + * order (from the last to the first bridge). > > + * > > + * This method is optional. > > + * > > + * RETURNS: > > + * zero if the check passed, a negative error code otherwise. > > + */ > > + int (*atomic_check)(struct drm_bridge *bridge, > > + struct drm_bridge_state *bridge_state, > > + struct drm_crtc_state *crtc_state, > > + struct drm_connector_state *conn_state); > > }; > > > > /** > > @@ -479,6 +499,9 @@ void drm_bridge_chain_mode_set(struct drm_encoder *encoder, > > void drm_bridge_chain_pre_enable(struct drm_encoder *encoder); > > void drm_bridge_chain_enable(struct drm_encoder *encoder); > > > > +int drm_atomic_bridge_chain_check(struct drm_encoder *encoder, > > + struct drm_crtc_state *crtc_state, > > + struct drm_connector_state *conn_state); > > void drm_atomic_bridge_chain_disable(struct drm_encoder *encoder, > > struct drm_atomic_state *state); > > void drm_atomic_bridge_chain_post_disable(struct drm_encoder *encoder, >
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index e76ec9648b6f..3fadde38ead7 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -445,12 +445,11 @@ mode_fixup(struct drm_atomic_state *state) encoder = new_conn_state->best_encoder; funcs = encoder->helper_private; - ret = drm_bridge_chain_mode_fixup(encoder, - &new_crtc_state->mode, - &new_crtc_state->adjusted_mode); - if (!ret) { - DRM_DEBUG_ATOMIC("Bridge fixup failed\n"); - return -EINVAL; + ret = drm_atomic_bridge_chain_check(encoder, new_crtc_state, + new_conn_state); + if (ret) { + DRM_DEBUG_ATOMIC("Bridge atomic check failed\n"); + return ret; } if (funcs && funcs->atomic_check) { diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 0528ca941855..dcad661daa74 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -583,6 +583,65 @@ void drm_atomic_bridge_chain_enable(struct drm_encoder *encoder, } EXPORT_SYMBOL(drm_atomic_bridge_chain_enable); +static int drm_atomic_bridge_check(struct drm_bridge *bridge, + struct drm_crtc_state *crtc_state, + struct drm_connector_state *conn_state) +{ + if (bridge->funcs->atomic_check) { + struct drm_bridge_state *bridge_state; + int ret; + + bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state, + bridge); + if (WARN_ON(!bridge_state)) + return -EINVAL; + + ret = bridge->funcs->atomic_check(bridge, bridge_state, + crtc_state, conn_state); + if (ret) + return ret; + } else if (bridge->funcs->mode_fixup) { + if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode, + &crtc_state->adjusted_mode)) + return -EINVAL; + } + + return 0; +} + +/** + * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain + * @encoder: encoder object + * @crtc_state: new CRTC state + * @conn_state: new connector state + * + * Calls &drm_bridge_funcs.atomic_check() (falls back on + * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain, + * starting from the last bridge to the first. These are called before calling + * &drm_encoder_helper_funcs.atomic_check() + * + * RETURNS: + * 0 on success, a negative error code on failure + */ +int drm_atomic_bridge_chain_check(struct drm_encoder *encoder, + struct drm_crtc_state *crtc_state, + struct drm_connector_state *conn_state) +{ + struct drm_bridge *bridge; + + list_for_each_entry_reverse(bridge, &encoder->bridge_chain, + chain_node) { + int ret; + + ret = drm_atomic_bridge_check(bridge, crtc_state, conn_state); + if (ret) + return ret; + } + + return 0; +} +EXPORT_SYMBOL(drm_atomic_bridge_chain_check); + /** * drm_atomic_helper_init_bridge_state() - Initializes a bridge state * @bridge this state is referring to diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index 9383b4e4b853..5d8fe3709bde 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -379,6 +379,26 @@ struct drm_bridge_funcs { */ void (*atomic_destroy_state)(struct drm_bridge *bridge, struct drm_bridge_state *state); + + /** + * @atomic_check: + * + * This method is responsible for checking bridge state correctness. + * It can also check the state of the surrounding components in chain + * to make sure the whole pipeline can work properly. + * + * &drm_bridge_funcs.atomic_check() hooks are called in reverse + * order (from the last to the first bridge). + * + * This method is optional. + * + * RETURNS: + * zero if the check passed, a negative error code otherwise. + */ + int (*atomic_check)(struct drm_bridge *bridge, + struct drm_bridge_state *bridge_state, + struct drm_crtc_state *crtc_state, + struct drm_connector_state *conn_state); }; /** @@ -479,6 +499,9 @@ void drm_bridge_chain_mode_set(struct drm_encoder *encoder, void drm_bridge_chain_pre_enable(struct drm_encoder *encoder); void drm_bridge_chain_enable(struct drm_encoder *encoder); +int drm_atomic_bridge_chain_check(struct drm_encoder *encoder, + struct drm_crtc_state *crtc_state, + struct drm_connector_state *conn_state); void drm_atomic_bridge_chain_disable(struct drm_encoder *encoder, struct drm_atomic_state *state); void drm_atomic_bridge_chain_post_disable(struct drm_encoder *encoder,
So that bridge drivers have a way to check/reject an atomic operation. The drm_atomic_bridge_chain_check() (which is just a wrapper around the ->atomic_check() hook) is called in place of drm_bridge_chain_mode_fixup() (when ->atomic_check() is not implemented, the core falls back to ->mode_fixup(), so the behavior should stay the same for existing bridge drivers). Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> --- drivers/gpu/drm/drm_atomic_helper.c | 11 +++--- drivers/gpu/drm/drm_bridge.c | 59 +++++++++++++++++++++++++++++ include/drm/drm_bridge.h | 23 +++++++++++ 3 files changed, 87 insertions(+), 6 deletions(-)