The initial purpose is for igt tests, but this would also be useful for compositors that wait until close to vblank deadline to make decisions about which frame to show. The igt tests can be found at: https://gitlab.freedesktop.org/robclark/igt-gpu-tools/-/commits/fence-deadline v2: Clarify the timebase, add link to igt tests v3: Use u64 value in ns to express deadline. v4: More doc
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| @@ -76,6 +76,27 @@ struct sync_file_info { · 75 unmodified lines | ||
| 76 | 76 | __u64 sync_fence_info; |
| 77 | 77 | }; |
| 78 | 78 | |
| 79 | +/** | |
| 80 | + * struct sync_set_deadline - SYNC_IOC_SET_DEADLINE - set a deadline hint on a fence | |
| 81 | + * @deadline_ns: absolute time of the deadline | |
| 82 | + * @pad: must be zero | |
| 83 | + * | |
| 84 | + * Allows userspace to set a deadline on a fence, see &dma_fence_set_deadline | |
| 85 | + * | |
| 86 | + * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank). For | |
| 87 | + * example | |
| 88 | + * | |
| 89 | + * clock_gettime(CLOCK_MONOTONIC, &t); | |
| 90 | + * deadline_ns = (t.tv_sec * 1000000000L) + t.tv_nsec + ns_until_deadline | |
| 91 | + */ | |
| 92 | +struct sync_set_deadline { | |
| 93 | + __u64 deadline_ns; | |
| 94 | + /* Not strictly needed for alignment but gives some possibility | |
| 95 | + * for future extension: | |
| 96 | + */ | |
| 97 | + __u64 pad; | |
| 98 | +}; | |
| 99 | + | |
| 79 | 100 | #define SYNC_IOC_MAGIC '>' |
| 80 | 101 | |
| 81 | 102 | /* |
| @@ -87,5 +108,6 @@ struct sync_file_info { · 5 unmodified lines | ||
| 87 | 108 | |
| 88 | 109 | #define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data) |
| 89 | 110 | #define SYNC_IOC_FILE_INFO _IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info) |
| 111 | +#define SYNC_IOC_SET_DEADLINE _IOW(SYNC_IOC_MAGIC, 5, struct sync_set_deadline) | |
| 90 | 112 | |
| 91 | 113 | #endif /* _UAPI_LINUX_SYNC_H */ |