因为Dma-fence是为跨设备间的同步而设计,这里有多种使用dma-fence方式: 1、explicit fencing:单个dma-fence通过以文件描述符(file descriptor)的形式暴露给用户层,用户层可以把该文件描述符传递给其他进程,因为是对应用层可见的,所以叫这类dma-fence为explicit fencing。 2、implicit fencing:其实就是对用户层不可见...
ioctl命令实现对dma-fence的操作: DMA_FENCE_IN_CMD:通过将fd将一个外来的fence传递到driver层,driver中先向该dma-fence添加一个callback回调函数,然后在显示调用wait函数,进程会阻塞直到该dma-fence变成signaled。 DMA_FENCE_OUT_CMD:将driver创建的dma-fence通过fd的方式导出到user层 DMA_FENCE_SIGNAL_CMD:对drive...
Dma-fence是用在kernel内部的跨设备(cross-device)的DMA操作同步原语,比如GPU向framebuffer做rendering,而displaying在读取framebuffer前需要确保GPU已完成rendering操作,即读操作之前,确保写操作已完成。 Dma-fence通常有两种状态,signaled 和 unsignaled。在这里,通常unsignaled表示buffer还在被使用,signaled表示buffer已使用...
dma-buf/dma-fence: Add deadline awareness Browse files Add a way to hint to the fence signaler of an upcoming deadline, such as vblank, which the fence waiter would prefer not to miss. This is to aid the fence signaler in making power management decisions, like boosting frequency as ...
dma-fence.h 70 changes: 63 additions & 7 deletions70drivers/dma-buf/dma-fence.c Original file line numberDiff line numberDiff line change Expand Up@@ -312,22 +312,25 @@ void __dma_fence_might_wait(void) /** *dma_fence_signal_locked- signal completion of a fence ...
Dma-fence是用在kernel内部的跨设备(cross-device)的DMA操作同步原语,比如GPU向framebuffer做rendering,而displaying在读取framebuffer前需要确保GPU已完成rendering操作,即读操作之前,确保写操作已完成。 Dma-fence通常有两种状态,signaled 和 unsignaled。在这里,通常unsignaled表示buffer还在被使用,signaled表示buffer已使用...
linux GPU上多个buffer间的同步之ww_mutex、dma_fence的使用 笔记 2021-01-26 21:50 −... -Yaong- 0 5485 DMA 2019-12-10 17:35 −基于 DMA 的硬件使用总线地址而非物理地址,总线地址是从设备角度上看到的内存地址,物理地址则是从 CPU 角度上看到的未经转换的内存地址(经过转换的为虚拟地址) 。内核...
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34 + static const char *host1x_syncpt_fence_get_driver_name(struct dma_fence *f) 35 + { 36 + return "host1x"; 37 + } 38 + 39 + static const char *host1x_syncpt_fence_get_timeline_name(struct dma_fence *f) 40 + { 41 + return "syncpoint"; 42 + } 43 + ...
This series adds a deadline hint to fences, so realtime deadlines such as vblank can be communicated to the fence signaller for power/ frequency management decisions. This is partially inspired by a trick i915 does, but implemented via dma-fence for a couple of reasons: 1) To continue to...