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Direct implementation of Chris code with a failure on the gbm_bo_map ask
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@mattkae
mattkae committed Sep 8, 2023
1 parent 751330b commit f42c534
Showing 1 changed file with 159 additions and 79 deletions.
238 changes: 159 additions & 79 deletions src/platforms/gbm-kms/server/kms/real_kms_output.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#include "kms-utils/kms_connector.h"
#include "mir/fatal.h"
#include "mir/log.h"
#include "display_helpers.h"
#include <string.h> // strcmp

#include <boost/throw_exception.hpp>
Expand All @@ -42,12 +43,14 @@ class RealKMSOutputContentMap : public mgg::KMSOutputContentMap
{
public:
RealKMSOutputContentMap(
size_t mapping_size,
void* map_data,
gbm_bo* bo,
mir::geometry::Size size,
mir::geometry::Stride stride,
uint32_t pixel_format,
unsigned char* data)
: mapping_size{mapping_size},
: map_data{map_data},
bo{bo},
size{size},
stride{stride},
pixel_format{pixel_format},
Expand All @@ -57,8 +60,12 @@ class RealKMSOutputContentMap : public mgg::KMSOutputContentMap

~RealKMSOutputContentMap() override
{
if (data)
munmap(static_cast<void*>(data), mapping_size);
if (bo)
{
if (map_data)
gbm_bo_unmap(bo, map_data);
gbm_bo_destroy(bo);
}
}

virtual auto get_size() -> mir::geometry::Size const& override
Expand All @@ -81,55 +88,9 @@ class RealKMSOutputContentMap : public mgg::KMSOutputContentMap
return data;
}

static auto try_create(
uint32_t stride,
uint32_t width,
uint32_t height,
int drm_fd,
int handle,
uint32_t offset,
uint32_t pixel_format) -> std::unique_ptr<RealKMSOutputContentMap>
{
int handle_fd;
int error;

if (pixel_format != DRM_FORMAT_XRGB8888) {
mir::log_error("Unsupported pixel format");
return nullptr;
}

error = drmPrimeHandleToFD(drm_fd, handle, 0, &handle_fd);
if (error < 0) {
mir::log_error("Failed to map the provided prime handle to a file descriptor. handle=%d\n",
handle);
return nullptr;
}

// Establish a memory map.
uint32_t size = height * stride;
auto map = static_cast<unsigned char *>(mmap(
0,
size,
PROT_READ,
MAP_SHARED,
handle_fd,
offset));

if (map == MAP_FAILED) {
mir::log_error("Failed to mmap");
return nullptr;
}

return std::make_unique<RealKMSOutputContentMap>(
size,
mir::geometry::Size{width, height},
mir::geometry::Stride {stride},
pixel_format,
map);
}

private:
size_t mapping_size;
void* map_data;
gbm_bo* bo;
mir::geometry::Size size;
mir::geometry::Stride stride;
mir::graphics::DRMFormat pixel_format;
Expand Down Expand Up @@ -713,41 +674,160 @@ int mgg::RealKMSOutput::drm_fd() const

std::shared_ptr<mgg::KMSOutputContentMap> mgg::RealKMSOutput::map_content() const
{
const int MAX_NUM_PLANES = 4;
auto buffer_id = saved_crtc.buffer_id;
kms::DRMModeResources resources{drm_fd()};
auto fb = resources.frame_buffer(buffer_id);

mir::log_info("Attempting to get a framebuffer from the current CRTC");

for (int handle_index = 0; handle_index < 4 && fb->handles[handle_index]; handle_index++) {
bool is_duplicate = false;

for (int other_handle_index = 0; other_handle_index < handle_index; other_handle_index++) {
if (fb->handles[handle_index] == fb->handles[other_handle_index]) {
is_duplicate = true;
break;
}
}

if (is_duplicate)
continue;

auto map = RealKMSOutputContentMap::try_create(
fb->pitches[handle_index],
fb->width,
fb->height,
drm_fd(),
fb->handles[handle_index],
fb->offsets[handle_index],
fb->pixel_format
);
struct ImportInfo
{
uint32_t handle = 0;
int fd = 0;
int stride = 0;
int offset = 0;
};

// Map each handle to its file descriptor, stride, and offset
// ImportInfo import_info[MAX_NUM_PLANES] = {};
// uint32_t num_handles = 0;
// for (int handle_index = 0; handle_index < MAX_NUM_PLANES; handle_index++) {
// auto handle = fb->handles[handle_index];
// if (!handle)
// continue;

// int fd;
// int err = drmPrimeHandleToFD(drm_fd_, handle, 0, &fd);
// if (err)
// {
// mir::log_error("Failed to map the provided prime handle to a file descriptor. handle=%d", handle);
// continue;
// }

// import_info[num_handles++] = {
// .handle = handle,
// .fd = fd,
// .stride = static_cast<int>(fb->pitches[handle_index]),
// .offset = static_cast<int>(fb->offsets[handle_index])
// };
// }

uint32_t num_handles = 0;
while (fb->handles[num_handles])
{
num_handles++;
}

if (num_handles == 0)
{
mir::log_error("Failed to find any handles to map");
return nullptr;
}

if (!map)
continue;
struct handle_to_fd
{
uint32_t handle;
int fd;
};
struct handle_to_fd handle_to_fd[4] = {};

return map;
for (int i = 0; i < 4; ++i)
{
uint32_t handle = fb->handles[i];
if (handle)
{
struct handle_to_fd* entry = handle_to_fd;
while(entry->handle && (entry->handle != handle))
{
++entry;
}
if (!entry->handle)
{
entry->handle = handle;
int err = drmPrimeHandleToFD(drm_fd_, entry->handle, 0, &entry->fd);
if (err)
{
log_error("Could not get prime fd from handle: %s (%i)\n", strerror(err), err);
exit(EXIT_FAILURE);
}
}
}
}

mir::log_info("Cannot get a framebuffer from the current CRTC");
return nullptr;
}
int plane_fds[MAX_NUM_PLANES] = {0};
for (uint32_t i = 0; i < num_handles; ++i)
{
struct handle_to_fd* entry = handle_to_fd;
while (entry->handle != fb->handles[i])
{
++entry;
}
plane_fds[i] = entry->fd;
}

struct gbm_import_fd_modifier_data import_data = {
.width=fb->width,
.height=fb->height,
.format=fb->pixel_format,
.num_fds=num_handles,
.fds={plane_fds[0], plane_fds[1], plane_fds[2], plane_fds[3]},
.strides={static_cast<int>(fb->pitches[0]), static_cast<int>(fb->pitches[1]), static_cast<int>(fb->pitches[2]), static_cast<int>(fb->pitches[3])},
.offsets={static_cast<int>(fb->offsets[0]), static_cast<int>(fb->offsets[1]), static_cast<int>(fb->offsets[2]), static_cast<int>(fb->offsets[3])},
.modifier=fb->modifier
};

// gbm_import_fd_modifier_data import_data = {
// .width=fb->width,
// .height=fb->height,
// .format=fb->pixel_format,
// .num_fds=num_handles,
// .fds={import_info[0].fd, import_info[1].fd, import_info[2].fd, import_info[3].fd},
// .strides={import_info[0].stride, import_info[1].stride, import_info[2].stride, import_info[3].stride},
// .offsets={import_info[0].offset, import_info[1].offset, import_info[2].offset, import_info[3].offset},
// .modifier=fb->modifier
// };

mg::gbm::helpers::GBMHelper helper{Fd{drm_fd()}};
gbm_bo* bo = gbm_bo_import(
helper.device,
GBM_BO_IMPORT_FD_MODIFIER,
&import_data,
0);

if (!bo)
{
mir::log_error("gbm_bo_import failed: %d", errno);
return nullptr;
}

void* map_data;
uint32_t map_stride;
errno = 0;
void* data = gbm_bo_map(
bo,
0,
0,
fb->width,
fb->height,
GBM_BO_TRANSFER_READ,
&map_stride,
&map_data);

if (data == MAP_FAILED || errno)
{
mir::log_error("gbm_bo_map failed: %d", errno);
//gbm_bo_destroy(bo);
//return nullptr;
}

mir::log_info("Successfully mapped buffer object: %u, %u, %u", fb->width, fb->height, map_stride);
return std::make_shared<RealKMSOutputContentMap>(
map_data,
bo,
geometry::Size{fb->width, fb->height},
geometry::Stride{map_stride},
fb->pixel_format,
static_cast<unsigned char*>(data));
}

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