AGP(4)                  NetBSD Kernel Interfaces Manual                 AGP(4)

agp -- accelerated graphics port driver
agp* at pchb?
The agp driver provides machine-independent support for the accelerated graphics port (AGP) found on many PC-based and PCI systems. The AGP specification was designed by Intel. The AGP chipset is positioned between the PCI-Host bridge and the graph- ics accelerator to provide a high-performance dedicated graphics bus for moving large amounts of data directly from host memory to the graphics accelerator. The specification currently supports a peak bandwidth of 528 MB/s. AGP uses a Graphics Address Remapping Table (GART) to provide a physically-contiguous view of scattered pages in host memory for DMA transfers. The agp driver supports the following chipsets: - ALI M1541 host-to-AGP bridge - AMD 751 and 761 host-to-AGP bridges - Intel 82810, 82810-DC100, 82810E, and 82815 SVGA controllers - SiS 5591 host-to-AGP bridge - VIA The agp driver also provides an interface to user processes for use by X servers. A user process communicates to the device initially by means of ioctl(2) calls. The calls supported are: AGPIOC_INFO Get AGP information, setting the members in the agp_info struc- ture as defined in <sys/agpio.h>: typedef struct _agp_info { agp_version version; /* version of the driver */ uint32_t bridge_id; /* bridge vendor/device */ uint32_t agp_mode; /* mode info of bridge */ off_t aper_base; /* base of aperture */ size_t aper_size; /* size of aperture */ size_t pg_total; /* max pages (swap + system) */ size_t pg_system; /* max pages (system) */ size_t pg_used; /* current pages used */ } agp_info; AGPIOC_ACQUIRE Acquire AGP. AGPIOC_RELEASE Release AGP. AGPIOC_SETUP Set up AGP, using the members in the agp_setup structure as defined in <sys/agpio.h>: typedef struct _agp_setup { uint32_t agp_mode; /* mode info of bridge */ } agp_setup; AGPIOC_ALLOCATE Allocate AGP space, using and setting the members in the agp_allocate structure as defined in <sys/agpio.h>: typedef struct _agp_allocate { int key; /* tag of allocation */ size_t pg_count; /* number of pages */ uint32_t type; /* 0 == normal, other devspec */ uint32_t physical; /* device specific (some devices * need a phys address of the * actual page behind the gatt * table) */ } agp_allocate; AGPIOC_DEALLOCATE Deallocate AGP space. AGPIOC_BIND Bind AGP space, using the members in the agp_bind structure as defined in <sys/agpio.h>: typedef struct _agp_bind { int key; /* tag of allocation */ off_t pg_start; /* starting page to populate */ } agp_bind; AGPIOC_UNBIND Unbind AGP space, using the members in the agp_unbind structure as defined in <sys/agpio.h>: typedef struct _agp_unbind { int key; /* tag of allocation */ uint32_t priority; /* priority for paging out */ } agp_unbind;
/dev/agp? AGP GART device special files /dev/agpgart AGP GART device special file
This short code fragment is an example of opening the AGP device and per- forming some basic operations: #include <sys/types.h> #include <sys/ioctl.h> #include <sys/agpio.h> #include <fcntl.h> #include <err.h> int main(int argc, char **argv) { int fd; agp_info info; agp_allocate alloc; agp_setup setup; agp_bind bind; agp_unbind unbind; fd = open("/dev/agp0", O_RDWR); if (fd < 0) err(1, "open"); if (ioctl(fd, AGPIOC_INFO, &info) < 0) err(2, "ioctl AGPIOC_INFO"); printf("version: %u.%u\n", info.version.major, info.version.minor); printf("id: %x\n", info.bridge_id); printf("mode: %x\n", info.agp_mode); printf("base: %x\n", info.aper_base); printf("size: %uM\n", info.aper_size); printf("total mem: %u\n", info.pg_total); printf("system mem: %u\n", info.pg_system); printf("used mem: %u\n\n", info.pg_used); setup.agp_mode = info.agp_mode; if (ioctl(fd, AGPIOC_SETUP, &setup) < 0) err(3, "ioctl AGPIOC_SETUP"); if (ioctl(fd, AGPIOC_ACQUIRE, 0) < 0) err(3, "ioctl AGPIOC_ACQUIRE"); alloc.type = 0; alloc.pg_count = 64; if (ioctl(fd, AGPIOC_ALLOCATE, &alloc) < 0) err(4, "ioctl AGPIOC_ALLOCATE"); printf("alloc key %d, paddr %x\n", alloc.key, alloc.physical); if (ioctl(fd, AGPIOC_INFO, &info) < 0) err(5, "ioctl AGPIOC_INFO"); bind.key = alloc.key; bind.pg_start = 0x1000; if (ioctl(fd, AGPIOC_BIND, &bind) < 0) err(6, "ioctl AGPIOC_BIND"); printf("used mem now: %u\n\n", info.pg_used); unbind.key = alloc.key; unbind.priority = 0; if (ioctl(fd, AGPIOC_UNBIND, &unbind) < 0) err(6, "ioctl AGPIOC_BIND"); if (ioctl(fd, AGPIOC_DEALLOCATE, &alloc.key) < 0) err(6, "ioctl AGPIOC_DEALLOCATE"); if (ioctl(fd, AGPIOC_RELEASE, 0) < 0) err(7, "ioctl AGPIOC_RELEASE"); close(fd); printf("agp test successful\n"); return 0; }
ioctl(2), pci(4)
The agp driver first appeared in FreeBSD 4.1. It was adopted in NetBSD 1.6. NetBSD 8.1 October 3, 2010 NetBSD 8.1

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