Get PCI vendor/device ID from userland
Hello, While looking at pipe_loader_drm.c in Mesa, I see that udev is used on Linux to get the PCI ID of the device. I understand that getting this information is a general need in libdrm, Mesa, and so on. Is there a portable way to obtain this? If not, what do you think about adding an ioctl in drm to get the PCI ID of an opened device? -- Jean-S?bastien P?dron
Questions about TTM buffer object maping
Le 11/07/2013 23:51, David Herrmann a ?crit : > ->vm_open() isn't called for the first mmap(), afaik (only called > during fork()s or similar). So the reference in ttm_bo_mmap() is a > replacement for the reference you take in the ->vm_open() callback. So the reference is acquired either in ttm_bo_mmap() or in ttm_bo_vm_open(), and always released in ttm_bo_vm_close(). Thanks to both of you! -- Jean-S?bastien P?dron
Questions about TTM buffer object maping
Hi, Thank you J?r?me and Daniel for your input, that's really helpful! I have another question: in ttm_bo_mmap(), a reference to the buffer object is acquired at the beginning of the function. Another reference is acquired in ttm_bo_vm_open() (released in ttm_bo_vm_close()). But where is the first reference released? -- Jean-S?bastien P?dron
Questions about TTM buffer object maping
Hello, I'm trying to understand how TTM buffer object mapping works on Linux, to make this behave properly on FreeBSD. Here's what I think I understand: When a buffer object is mmap()'d, ttm_bo_vm_open() is called. When there's a page fault, the page is looked up and inserted in the VMA using vm_insert_mixed(). When a buffer object is munmap()'d, ttm_bo_vm_close() is called, which drops a reference. When the last reference is dropped, the buffer object is destroyed. What's still not clear to me is how munmap() works here. After talking about this on IRC with some people, I think that unmap_mapping_range() (called by ttm_bo_unmap_virtual_locked()) is equivalent to calling munmap() from userland. Is that true? When a buffer object is moved, what happens to the mapping? In particular, I see in ttm_bo_move_accel_cleanup() that the ttm structure can be transferred to ghost_obj, which is destroyed shortly after. This ends up in ttm_put_pages() which uses __free_page(), for each page of the buffer object. At this stage, is the ghost object already munmap()'d? Or does __free_page() unmap a page implicitly (ie. remove it from VMA)? Sorry if my questions are stupid, I'm rather new to memory management. -- Jean-S?bastien P?dron
Re: Questions about TTM buffer object maping
Le 11/07/2013 23:51, David Herrmann a écrit : -vm_open() isn't called for the first mmap(), afaik (only called during fork()s or similar). So the reference in ttm_bo_mmap() is a replacement for the reference you take in the -vm_open() callback. So the reference is acquired either in ttm_bo_mmap() or in ttm_bo_vm_open(), and always released in ttm_bo_vm_close(). Thanks to both of you! -- Jean-Sébastien Pédron ___ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
Questions about TTM buffer object maping
Hello, I'm trying to understand how TTM buffer object mapping works on Linux, to make this behave properly on FreeBSD. Here's what I think I understand: When a buffer object is mmap()'d, ttm_bo_vm_open() is called. When there's a page fault, the page is looked up and inserted in the VMA using vm_insert_mixed(). When a buffer object is munmap()'d, ttm_bo_vm_close() is called, which drops a reference. When the last reference is dropped, the buffer object is destroyed. What's still not clear to me is how munmap() works here. After talking about this on IRC with some people, I think that unmap_mapping_range() (called by ttm_bo_unmap_virtual_locked()) is equivalent to calling munmap() from userland. Is that true? When a buffer object is moved, what happens to the mapping? In particular, I see in ttm_bo_move_accel_cleanup() that the ttm structure can be transferred to ghost_obj, which is destroyed shortly after. This ends up in ttm_put_pages() which uses __free_page(), for each page of the buffer object. At this stage, is the ghost object already munmap()'d? Or does __free_page() unmap a page implicitly (ie. remove it from VMA)? Sorry if my questions are stupid, I'm rather new to memory management. -- Jean-Sébastien Pédron ___ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
