diff options
Diffstat (limited to 'drivers/char/agp/generic.c')
| -rw-r--r-- | drivers/char/agp/generic.c | 36 |
1 files changed, 33 insertions, 3 deletions
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c index 5ff457b41ef..3491d6f84bc 100644 --- a/drivers/char/agp/generic.c +++ b/drivers/char/agp/generic.c @@ -419,6 +419,31 @@ static void agp_v2_parse_one(u32 *requested_mode, u32 *bridge_agpstat, u32 *vga_ *requested_mode &= ~AGP2_RESERVED_MASK; } + /* + * Some dumb bridges are programmed to disobey the AGP2 spec. + * This is likely a BIOS misprogramming rather than poweron default, or + * it would be a lot more common. + * https://bugs.freedesktop.org/show_bug.cgi?id=8816 + * AGPv2 spec 6.1.9 states: + * The RATE field indicates the data transfer rates supported by this + * device. A.G.P. devices must report all that apply. + * Fix them up as best we can. + */ + switch (*bridge_agpstat & 7) { + case 4: + *bridge_agpstat |= (AGPSTAT2_2X | AGPSTAT2_1X); + printk(KERN_INFO PFX "BIOS bug. AGP bridge claims to only support x4 rate" + "Fixing up support for x2 & x1\n"); + break; + case 2: + *bridge_agpstat |= AGPSTAT2_1X; + printk(KERN_INFO PFX "BIOS bug. AGP bridge claims to only support x2 rate" + "Fixing up support for x1\n"); + break; + default: + break; + } + /* Check the speed bits make sense. Only one should be set. */ tmp = *requested_mode & 7; switch (tmp) { @@ -940,6 +965,9 @@ int agp_generic_insert_memory(struct agp_memory * mem, off_t pg_start, int type) if (!bridge) return -EINVAL; + if (mem->page_count == 0) + return 0; + temp = bridge->current_size; switch (bridge->driver->size_type) { @@ -991,8 +1019,8 @@ int agp_generic_insert_memory(struct agp_memory * mem, off_t pg_start, int type) for (i = 0, j = pg_start; i < mem->page_count; i++, j++) { writel(bridge->driver->mask_memory(bridge, mem->memory[i], mem->type), bridge->gatt_table+j); - readl(bridge->gatt_table+j); /* PCI Posting. */ } + readl(bridge->gatt_table+j-1); /* PCI Posting. */ bridge->driver->tlb_flush(mem); return 0; @@ -1009,6 +1037,9 @@ int agp_generic_remove_memory(struct agp_memory *mem, off_t pg_start, int type) if (!bridge) return -EINVAL; + if (mem->page_count == 0) + return 0; + if (type != 0 || mem->type != 0) { /* The generic routines know nothing of memory types */ return -EINVAL; @@ -1017,10 +1048,9 @@ int agp_generic_remove_memory(struct agp_memory *mem, off_t pg_start, int type) /* AK: bogus, should encode addresses > 4GB */ for (i = pg_start; i < (mem->page_count + pg_start); i++) { writel(bridge->scratch_page, bridge->gatt_table+i); - readl(bridge->gatt_table+i); /* PCI Posting. */ } + readl(bridge->gatt_table+i-1); /* PCI Posting. */ - global_cache_flush(); bridge->driver->tlb_flush(mem); return 0; } |