diff options
Diffstat (limited to 'lib/igt_debugfs.c')
| -rw-r--r-- | lib/igt_debugfs.c | 173 |
1 files changed, 167 insertions, 6 deletions
diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c index 131dccc0..5c029019 100644 --- a/lib/igt_debugfs.c +++ b/lib/igt_debugfs.c @@ -34,9 +34,54 @@ #include "igt_display.h" #include "igt_debugfs.h" +/** + * SECTION:igt_debugfs + * @short_description: Support code for debugfs features + * @title: i-g-t debugfs + * + * This library provides helpers to access debugfs features. On top of some + * basic functions to access debugfs files with e.g. igt_debugfs_open() it also + * provides higher-level wrappers for some debugfs features + * + * # Pipe CRC Support + * + * This library wraps up the kernel's support for capturing pipe CRCs into a + * neat and tidy package. For the datailed usage see all the functions which + * work on #igt_pipe_crc_t. This is supported on all platforms and outputs. + * + * Actually using pipe CRCs to write modeset tests is a bit tricky though, so + * there is no way to directly check a CRC: Both the details of the plane + * blending, color correction and other hardware and how exactly the CRC is + * computed at each tap point vary by hardware generation and are not disclosed. + * + * The only way to use #igt_crc_t CRCs therefors is to compare CRCs among each + * another either for equality or difference. Otherwise CRCs must be treated as + * completely opaque values. Note that not even CRCs from different pipes or tap + * points on the same platform can be compared. Hence only use igt_crc_is_null() + * and igt_crc_equal() to insepct CRC values captured by the same + * #igt_pipe_crc_t object. + * + * # Other debugfs interface wrappers + * + * This covers the miscellaneous debugfs interface wrappers: + * + * - drm/i915 supports interfaces to evict certain clases of gem buffer objects, + * see igt_drop_caches_set(). + * + * - drm/i915 supports an interface to disable prefaulting, useful to test + * slowpaths in ioctls. See igt_disable_prefault(). + */ + /* * General debugfs helpers */ + +/** + * igt_debugfs_init: + * @debugfs: debugfs access structure to initialize + * + * Initializes the debugfs access helper library. + */ void igt_debugfs_init(igt_debugfs_t *debugfs) { const char *path = "/sys/kernel/debug"; @@ -71,6 +116,15 @@ find_minor: igt_fail(4); } +/** + * igt_debugfs_open: + * @debugfs: debugfs access structure + * @filename: name of the debugfs node to open + * @mode: mode bits as used by open() + * + * This opens a debugfs file as a Unix file descriptor. The filename should be + * relative to the drm device's root, i.e without "drm/<minor>". + */ int igt_debugfs_open(igt_debugfs_t *debugfs, const char *filename, int mode) { char buf[1024]; @@ -79,6 +133,15 @@ int igt_debugfs_open(igt_debugfs_t *debugfs, const char *filename, int mode) return open(buf, mode); } +/** + * igt_debugfs_fopen: + * @debugfs: debugfs access structure + * @filename: name of the debugfs node to open + * @mode: mode string as used by fopen() + * + * This opens a debugfs file as a libc FILE. The filename should be + * relative to the drm device's root, i.e without "drm/<minor>". + */ FILE *igt_debugfs_fopen(igt_debugfs_t *debugfs, const char *filename, const char *mode) { @@ -92,6 +155,13 @@ FILE *igt_debugfs_fopen(igt_debugfs_t *debugfs, const char *filename, * Pipe CRC */ +/** + * igt_crc_is_null: + * @crc: pipe CRC value to check + * + * Returns: True if the CRC is null/invalid, false if it represents a captured + * valid CRC. + */ bool igt_crc_is_null(igt_crc_t *crc) { int i; @@ -103,6 +173,15 @@ bool igt_crc_is_null(igt_crc_t *crc) return true; } +/** + * igt_crc_equal: + * @a: first pipe CRC value + * @b: second pipe CRC value + * + * Compares two CRC values. + * + * Returns: Retruns true if the two CRCs match, false otherwise. + */ bool igt_crc_equal(igt_crc_t *a, igt_crc_t *b) { int i; @@ -117,6 +196,16 @@ bool igt_crc_equal(igt_crc_t *a, igt_crc_t *b) return true; } +/** + * igt_crc_to_string: + * @crc: pipe CRC value to print + * + * This formats @crc into a string buffer which is owned by igt_crc_to_string(). + * The next call will override the buffer again, which makes this multithreading + * unsafe. + * + * This should only ever be used for diagnostic debug output. + */ char *igt_crc_to_string(igt_crc_t *crc) { char buf[128]; @@ -205,6 +294,14 @@ static void pipe_crc_exit_handler(int sig) igt_pipe_crc_reset(); } +/** + * igt_pipe_crc_check: + * @debugfs: debugfs access structure + * + * Convenience helper to check whether pipe CRC capturing is supported by the + * kernel. Uses igt_skip to automatically skip the test/subtest if this isn't + * the case. + */ void igt_pipe_crc_check(igt_debugfs_t *debugfs) { const char *cmd = "pipe A none"; @@ -223,6 +320,18 @@ void igt_pipe_crc_check(igt_debugfs_t *debugfs) fclose(ctl); } +/** + * igt_pipe_crc_new: + * @debugfs: debugfs access structure + * @pipe: display pipe to use as source + * @source: CRC tap point to use as source + * + * This sets up a new pipe CRC capture object for the given @pipe and @source. + * + * Returns: A pipe CRC object if the given @pipe and @source is available, NULL + * otherwise. Tests can use this to intelligently skip if they require a + * specific pipe CRC source to function properly. + */ igt_pipe_crc_t * igt_pipe_crc_new(igt_debugfs_t *debugfs, enum pipe pipe, enum intel_pipe_crc_source source) @@ -258,6 +367,12 @@ igt_pipe_crc_new(igt_debugfs_t *debugfs, enum pipe pipe, return pipe_crc; } +/** + * igt_pipe_crc_free: + * @pipe_crc: pipe CRC object + * + * Frees all resources associated with @pipe_crc. + */ void igt_pipe_crc_free(igt_pipe_crc_t *pipe_crc) { if (!pipe_crc) @@ -268,6 +383,12 @@ void igt_pipe_crc_free(igt_pipe_crc_t *pipe_crc) free(pipe_crc); } +/** + * igt_pipe_crc_start: + * @pipe_crc: pipe CRC object + * + * Starts the CRC capture process on @pipe_crc. + */ void igt_pipe_crc_start(igt_pipe_crc_t *pipe_crc) { igt_crc_t *crcs = NULL; @@ -282,6 +403,12 @@ void igt_pipe_crc_start(igt_pipe_crc_t *pipe_crc) free(crcs); } +/** + * igt_pipe_crc_stop: + * @pipe_crc: pipe CRC object + * + * Stops the CRC capture process on @pipe_crc. + */ void igt_pipe_crc_stop(igt_pipe_crc_t *pipe_crc) { char buf[32]; @@ -315,9 +442,18 @@ static bool read_one_crc(igt_pipe_crc_t *pipe_crc, igt_crc_t *out) return true; } -/* - * Read @n_crcs from the @pipe_crc. This function blocks until @n_crcs are - * retrieved. +/** + * igt_pipe_crc_get_crcs: + * @pipe_crc: pipe CRC object + * @n_crcs: number of CRCs to capture + * @out_crcs: buffer pointer for the captured CRC values + * + * Read @n_crcs from @pipe_crc. This function blocks until @n_crcs are + * retrieved. @out_crcs is alloced by this function and must be released with + * free() by the caller. + * + * Callers must start and stop the capturing themselves by calling + * igt_pipe_crc_start() and igt_pipe_crc_stop(). */ void igt_pipe_crc_get_crcs(igt_pipe_crc_t *pipe_crc, int n_crcs, @@ -340,9 +476,13 @@ igt_pipe_crc_get_crcs(igt_pipe_crc_t *pipe_crc, int n_crcs, *out_crcs = crcs; } -/* - * Read 1 CRC from @pipe_crc. This function blocks until the CRC is retrieved. - * @out_crc must be allocated by the caller. +/** + * igt_pipe_crc_collect_crc: + * @pipe_crc: pipe CRC object + * @out_crc: buffer for the captured CRC values + * + * Read a single CRC from @pipe_crc. This function blocks until the CRC is + * retrieved. @out_crc must be allocated by the caller. * * This function takes care of the pipe_crc book-keeping, it will start/stop * the collection of the CRC. @@ -358,6 +498,13 @@ void igt_pipe_crc_collect_crc(igt_pipe_crc_t *pipe_crc, igt_crc_t *out_crc) * Drop caches */ +/** + * igt_drop_caches_set: + * @val: bitmask for DROP_* values + * + * This calls the debugfs interface the drm/i915 GEM driver exposes to drop or + * evict certain classes of gem buffer objects. + */ void igt_drop_caches_set(uint64_t val) { igt_debugfs_t debugfs; @@ -406,6 +553,15 @@ static void enable_prefault_at_exit(int sig) igt_enable_prefault(); } +/** + * igt_disable_prefault: + * + * Disable prefaulting in certain gem ioctls through the debugfs interface. As + * usual this installs an exit handler to clean up and re-enable prefaulting + * even when the test exited abnormally. + * + * igt_enable_prefault() will enable normale operation again. + */ void igt_disable_prefault(void) { igt_prefault_control(false); @@ -413,6 +569,11 @@ void igt_disable_prefault(void) igt_install_exit_handler(enable_prefault_at_exit); } +/** + * igt_enable_prefault: + * + * Enable prefault (again) through the debugfs interface. + */ void igt_enable_prefault(void) { igt_prefault_control(true); |