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Commit 3dfbf2d3 authored by Boris Brezillon's avatar Boris Brezillon
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Revert "drm/bridge: Add the necessary bits to support bus format negotiation" 

This reverts commit e351e4d5 ("drm/bridge: Add the necessary bits
to support bus format negotiation"). Commit 6ed7e962 ("drm/bridge:
Add a drm_bridge_state object") introduced a circular dependency
between drm.ko and drm_kms_helper.ko which uncovered a misdesign in
how the whole thing was implemented. Let's revert all patches depending
on the bridge_state infrastructure for now.
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Acked-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200107185807.606999-3-boris.brezillon@collabora.com
parent 6ae1a4bb
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Showing with 1 addition and 390 deletions
drivers/gpu/drm/drm_bridge.c
View file @ 3dfbf2d3
......@@ -671,261 +671,13 @@ static int drm_atomic_bridge_check(struct drm_bridge *bridge,
return 0;
}
/**
* drm_atomic_helper_bridge_propagate_bus_fmt() - Propagate output format to
* the input end of a bridge
* @bridge: bridge control structure
* @bridge_state: new bridge state
* @crtc_state: new CRTC state
* @conn_state: new connector state
* @output_fmt: tested output bus format
* @num_input_fmts: will contain the size of the returned array
*
* This helper is a pluggable implementation of the
* &drm_bridge_funcs.atomic_get_input_bus_fmts operation for bridges that don't
* modify the bus configuration between their input and their output. It
* returns an array of input formats with a single element set to @output_fmt.
*
* RETURNS:
* a valid format array of size @num_input_fmts, or NULL if the allocation
* failed
*/
u32 *
drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
struct drm_bridge_state *bridge_state,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state,
u32 output_fmt,
unsigned int *num_input_fmts)
{
u32 *input_fmts;
input_fmts = kzalloc(sizeof(*input_fmts), GFP_KERNEL);
if (!input_fmts) {
*num_input_fmts = 0;
return NULL;
}
*num_input_fmts = 1;
input_fmts[0] = output_fmt;
return input_fmts;
}
EXPORT_SYMBOL(drm_atomic_helper_bridge_propagate_bus_fmt);
static int select_bus_fmt_recursive(struct drm_bridge *first_bridge,
struct drm_bridge *cur_bridge,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state,
u32 out_bus_fmt)
{
struct drm_bridge_state *cur_state;
unsigned int num_in_bus_fmts, i;
struct drm_bridge *prev_bridge;
u32 *in_bus_fmts;
int ret;
prev_bridge = drm_bridge_get_prev_bridge(cur_bridge);
cur_state = drm_atomic_get_new_bridge_state(crtc_state->state,
cur_bridge);
if (WARN_ON(!cur_state))
return -EINVAL;
/*
* If bus format negotiation is not supported by this bridge, let's
* pass MEDIA_BUS_FMT_FIXED to the previous bridge in the chain and
* hope that it can handle this situation gracefully (by providing
* appropriate default values).
*/
if (!cur_bridge->funcs->atomic_get_input_bus_fmts) {
if (cur_bridge != first_bridge) {
ret = select_bus_fmt_recursive(first_bridge,
prev_bridge, crtc_state,
conn_state,
MEDIA_BUS_FMT_FIXED);
if (ret)
return ret;
}
cur_state->input_bus_cfg.format = MEDIA_BUS_FMT_FIXED;
cur_state->output_bus_cfg.format = out_bus_fmt;
return 0;
}
in_bus_fmts = cur_bridge->funcs->atomic_get_input_bus_fmts(cur_bridge,
cur_state,
crtc_state,
conn_state,
out_bus_fmt,
&num_in_bus_fmts);
if (!num_in_bus_fmts)
return -ENOTSUPP;
else if (!in_bus_fmts)
return -ENOMEM;
if (first_bridge == cur_bridge) {
cur_state->input_bus_cfg.format = in_bus_fmts[0];
cur_state->output_bus_cfg.format = out_bus_fmt;
kfree(in_bus_fmts);
return 0;
}
for (i = 0; i < num_in_bus_fmts; i++) {
ret = select_bus_fmt_recursive(first_bridge, prev_bridge,
crtc_state, conn_state,
in_bus_fmts[i]);
if (ret != -ENOTSUPP)
break;
}
if (!ret) {
cur_state->input_bus_cfg.format = in_bus_fmts[i];
cur_state->output_bus_cfg.format = out_bus_fmt;
}
kfree(in_bus_fmts);
return ret;
}
/*
* This function is called by &drm_atomic_bridge_chain_check() just before
* calling &drm_bridge_funcs.atomic_check() on all elements of the chain.
* It performs bus format negotiation between bridge elements. The negotiation
* happens in reverse order, starting from the last element in the chain up to
* @bridge.
*
* Negotiation starts by retrieving supported output bus formats on the last
* bridge element and testing them one by one. The test is recursive, meaning
* that for each tested output format, the whole chain will be walked backward,
* and each element will have to choose an input bus format that can be
* transcoded to the requested output format. When a bridge element does not
* support transcoding into a specific output format -ENOTSUPP is returned and
* the next bridge element will have to try a different format. If none of the
* combinations worked, -ENOTSUPP is returned and the atomic modeset will fail.
*
* This implementation is relying on
* &drm_bridge_funcs.atomic_get_output_bus_fmts() and
* &drm_bridge_funcs.atomic_get_input_bus_fmts() to gather supported
* input/output formats.
*
* When &drm_bridge_funcs.atomic_get_output_bus_fmts() is not implemented by
* the last element of the chain, &drm_atomic_bridge_chain_select_bus_fmts()
* tries a single format: &drm_connector.display_info.bus_formats[0] if
* available, MEDIA_BUS_FMT_FIXED otherwise.
*
* When &drm_bridge_funcs.atomic_get_input_bus_fmts() is not implemented,
* &drm_atomic_bridge_chain_select_bus_fmts() skips the negotiation on the
* bridge element that lacks this hook and asks the previous element in the
* chain to try MEDIA_BUS_FMT_FIXED. It's up to bridge drivers to decide what
* to do in that case (fail if they want to enforce bus format negotiation, or
* provide a reasonable default if they need to support pipelines where not
* all elements support bus format negotiation).
*/
static int
drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
{
struct drm_connector *conn = conn_state->connector;
struct drm_encoder *encoder = bridge->encoder;
struct drm_bridge_state *last_bridge_state;
unsigned int i, num_out_bus_fmts;
struct drm_bridge *last_bridge;
u32 *out_bus_fmts;
int ret = 0;
last_bridge = list_last_entry(&encoder->bridge_chain,
struct drm_bridge, chain_node);
last_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
last_bridge);
if (WARN_ON(!last_bridge_state))
return -EINVAL;
if (last_bridge->funcs->atomic_get_output_bus_fmts) {
const struct drm_bridge_funcs *funcs = last_bridge->funcs;
out_bus_fmts = funcs->atomic_get_output_bus_fmts(last_bridge,
last_bridge_state,
crtc_state,
conn_state,
&num_out_bus_fmts);
if (!num_out_bus_fmts)
return -ENOTSUPP;
else if (!out_bus_fmts)
return -ENOMEM;
} else {
num_out_bus_fmts = 1;
out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
if (!out_bus_fmts)
return -ENOMEM;
if (conn->display_info.num_bus_formats &&
conn->display_info.bus_formats)
out_bus_fmts[0] = conn->display_info.bus_formats[0];
else
out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
}
for (i = 0; i < num_out_bus_fmts; i++) {
ret = select_bus_fmt_recursive(bridge, last_bridge, crtc_state,
conn_state, out_bus_fmts[i]);
if (ret != -ENOTSUPP)
break;
}
kfree(out_bus_fmts);
return ret;
}
static void
drm_atomic_bridge_propagate_bus_flags(struct drm_bridge *bridge,
struct drm_connector *conn,
struct drm_atomic_state *state)
{
struct drm_bridge_state *bridge_state, *next_bridge_state;
struct drm_bridge *next_bridge;
u32 output_flags;
bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
next_bridge = drm_bridge_get_next_bridge(bridge);
/*
* Let's try to apply the most common case here, that is, propagate
* display_info flags for the last bridge, and propagate the input
* flags of the next bridge element to the output end of the current
* bridge when the bridge is not the last one.
* There are exceptions to this rule, like when signal inversion is
* happening at the board level, but that's something drivers can deal
* with from their &drm_bridge_funcs.atomic_check() implementation by
* simply overriding the flags value we've set here.
*/
if (!next_bridge) {
output_flags = conn->display_info.bus_flags;
} else {
next_bridge_state = drm_atomic_get_new_bridge_state(state,
next_bridge);
output_flags = next_bridge_state->input_bus_cfg.flags;
}
bridge_state->output_bus_cfg.flags = output_flags;
/*
* Propage the output flags to the input end of the bridge. Again, it's
* not necessarily what all bridges want, but that's what most of them
* do, and by doing that by default we avoid forcing drivers to
* duplicate the "dummy propagation" logic.
*/
bridge_state->input_bus_cfg.flags = output_flags;
}
/**
* drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain
* @bridge: bridge control structure
* @crtc_state: new CRTC state
* @conn_state: new connector state
*
* First trigger a bus format negotiation before calling
* &drm_bridge_funcs.atomic_check() (falls back on
* 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()
......@@ -937,29 +689,12 @@ int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
{
struct drm_connector *conn = conn_state->connector;
struct drm_encoder *encoder = bridge->encoder;
struct drm_bridge *iter;
int ret;
ret = drm_atomic_bridge_chain_select_bus_fmts(bridge, crtc_state,
conn_state);
if (ret)
return ret;
list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
int ret;
/*
* Bus flags are propagated by default. If a bridge needs to
* tweak the input bus flags for any reason, it should happen
* in its &drm_bridge_funcs.atomic_check() implementation such
* that preceding bridges in the chain can propagate the new
* bus flags.
*/
drm_atomic_bridge_propagate_bus_flags(iter, conn,
crtc_state->state);
ret = drm_atomic_bridge_check(iter, crtc_state, conn_state);
if (ret)
return ret;
......
include/drm/drm_bridge.h
View file @ 3dfbf2d3
......@@ -35,38 +35,6 @@ struct drm_bridge;
struct drm_bridge_timings;
struct drm_panel;
/**
* struct drm_bus_cfg - bus configuration
*
* This structure stores the configuration of a physical bus between two
* components in an output pipeline, usually between two bridges, an encoder
* and a bridge, or a bridge and a connector.
*
* The bus configuration is stored in &drm_bridge_state separately for the
* input and output buses, as seen from the point of view of each bridge. The
* bus configuration of a bridge output is usually identical to the
* configuration of the next bridge's input, but may differ if the signals are
* modified between the two bridges, for instance by an inverter on the board.
* The input and output configurations of a bridge may differ if the bridge
* modifies the signals internally, for instance by performing format
* conversion, or modifying signals polarities.
*/
struct drm_bus_cfg {
/**
* @format: format used on this bus (one of the MEDIA_BUS_FMT_* format)
*
* This field should not be directly modified by drivers
* (&drm_atomic_bridge_chain_select_bus_fmts() takes care of the bus
* format negotiation).
*/
u32 format;
/**
* @flags: DRM_BUS_* flags used on this bus
*/
u32 flags;
};
/**
* struct drm_bridge_state - Atomic bridge state object
* @base: inherit from &drm_private_state
......@@ -76,16 +44,6 @@ struct drm_bridge_state {
struct drm_private_state base;
struct drm_bridge *bridge;
/**
* @input_bus_cfg: input bus configuration
*/
struct drm_bus_cfg input_bus_cfg;
/**
* @output_bus_cfg: input bus configuration
*/
struct drm_bus_cfg output_bus_cfg;
};
static inline struct drm_bridge_state *
......@@ -429,72 +387,6 @@ struct drm_bridge_funcs {
void (*atomic_destroy_state)(struct drm_bridge *bridge,
struct drm_bridge_state *state);
/**
* @atomic_get_output_bus_fmts:
*
* Return the supported bus formats on the output end of a bridge.
* The returned array must be allocated with kmalloc() and will be
* freed by the caller. If the allocation fails, NULL should be
* returned. num_output_fmts must be set to the returned array size.
* Formats listed in the returned array should be listed in decreasing
* preference order (the core will try all formats until it finds one
* that works).
*
* This method is only called on the last element of the bridge chain
* as part of the bus format negotiation process that happens in
* &drm_atomic_bridge_chain_select_bus_fmts().
* This method is optional. When not implemented, the core will
* fall back to &drm_connector.display_info.bus_formats[0] if
* &drm_connector.display_info.num_bus_formats > 0,
* or to MEDIA_BUS_FMT_FIXED otherwise.
*/
u32 *(*atomic_get_output_bus_fmts)(struct drm_bridge *bridge,
struct drm_bridge_state *bridge_state,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state,
unsigned int *num_output_fmts);
/**
* @atomic_get_input_bus_fmts:
*
* Return the supported bus formats on the input end of a bridge for
* a specific output bus format.
*
* The returned array must be allocated with kmalloc() and will be
* freed by the caller. If the allocation fails, NULL should be
* returned. num_output_fmts must be set to the returned array size.
* Formats listed in the returned array should be listed in decreasing
* preference order (the core will try all formats until it finds one
* that works). When the format is not supported NULL should be
* returned and *num_output_fmts should be set to 0.
*
* This method is called on all elements of the bridge chain as part of
* the bus format negotiation process that happens in
* &drm_atomic_bridge_chain_select_bus_fmts().
* This method is optional. When not implemented, the core will bypass
* bus format negotiation on this element of the bridge without
* failing, and the previous element in the chain will be passed
* MEDIA_BUS_FMT_FIXED as its output bus format.
*
* Bridge drivers that need to support being linked to bridges that are
* not supporting bus format negotiation should handle the
* output_fmt == MEDIA_BUS_FMT_FIXED case appropriately, by selecting a
* sensible default value or extracting this information from somewhere
* else (FW property, &drm_display_mode, &drm_display_info, ...)
*
* Note: Even if input format selection on the first bridge has no
* impact on the negotiation process (bus format negotiation stops once
* we reach the first element of the chain), drivers are expected to
* return accurate input formats as the input format may be used to
* configure the CRTC output appropriately.
*/
u32 *(*atomic_get_input_bus_fmts)(struct drm_bridge *bridge,
struct drm_bridge_state *bridge_state,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state,
u32 output_fmt,
unsigned int *num_input_fmts);
/**
* @atomic_check:
*
......@@ -509,14 +401,6 @@ struct drm_bridge_funcs {
* called when &drm_bridge_funcs.atomic_check() is implemented, so only
* one of them should be provided.
*
* If drivers need to tweak &drm_bridge_state.input_bus_cfg.flags or
* &drm_bridge_state.output_bus_cfg.flags it should should happen in
* this function. By default the &drm_bridge_state.output_bus_cfg.flags
* field is set to the next bridge
* &drm_bridge_state.input_bus_cfg.flags value or
* &drm_connector.display_info.bus_flags if the bridge is the last
* element in the chain.
*
* RETURNS:
* zero if the check passed, a negative error code otherwise.
*/
......@@ -704,14 +588,6 @@ void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
struct drm_atomic_state *state);
u32 *
drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
struct drm_bridge_state *bridge_state,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state,
u32 output_fmt,
unsigned int *num_input_fmts);
void __drm_atomic_helper_bridge_reset(struct drm_bridge *bridge,
struct drm_bridge_state *state);
void __drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge,
......
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