BS DRM

BS DRM is a library to factor out most of the boilerplate found in programs written against DRM.

Dependencies

• Clang or GCC with -std=gnu99
• libgbm
• libdrm

Features

• Opens DRM devices
• Creates display pipelines
• Allocates buffer objects with framebuffers
• Dumb maps buffer objects

Goals

(in order of priority)

• Useful
• Consistent and guessable API
• Easy to read
• Code is documentation
• 0 warnings from Clang or GCC
• Make errors easy to debug
• Fun

Code Philosophy

• This library is meant to be consumed by applications, not other libraries
• Applications usually can't recover from errors
• Corollary: returning error codes to applications is a waste of programmer time
• Badly behaving applications should fail fast
• Asserts fail fast
• Use asserts to make bad applications fail fast
• Make code style consistent with clang-format

Naming Rules

• File names: .c
• Functions: start with bs__
• Constructor functions: suffix with “new”
• Destructor functions: suffix with “destroy”
• Conversion functions: suffix with “create”
• Functions that overload: put overload name at the very end

Build Example

Define CC CFLAGS and LDFLAGS for your device. Then run the following from the top level directory:

${CC} ${CFLAGS} -c src/drm_fb.c -o drm_fb.o || exit 1
${CC} ${CFLAGS} -c src/drm_open.c -o drm_open.o || exit 1
${CC} ${CFLAGS} -c src/drm_pipe.c -o drm_pipe.o || exit 1
${CC} ${CFLAGS} -c src/pipe.c -o pipe.o || exit 1
${CC} ${CFLAGS} -c example/stripe.c -o stripe.o || exit 1
${CC} ${LDFLAGS} \
    pipe.o \
    drm_pipe.o \
    drm_fb.o \
    drm_open.o \
    stripe.o -o bstest || exit 1

Clang Format Example

If you want to format gamma_test.c, first go to the drm-tests source directory and then run:

clang-format -style=file -i gamma_test.c

The -style=file argument will cause clang-format to search recursively upwards for the .clang-format style file, which is in drm-tests.

Upcoming Features

• Vsync
• Atomic Commit
• Multi-card and multi-monitor
• Keyboard/Mouse input for debugging
• Dump buffer output for debugging

What does BS stand for?

BS does't stand for anything.