Date: Mon, 27 Oct 2014 16:16:31 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Tijl Coosemans <tijl@FreeBSD.org> Cc: x11@FreeBSD.org, dumbbell@FreeBSD.org Subject: Re: [rfc] Radeon AGP support patches Message-ID: <20141027141631.GX1877@kib.kiev.ua> In-Reply-To: <20141026162442.1330d4c3@kalimero.tijl.coosemans.org> References: <20141026162442.1330d4c3@kalimero.tijl.coosemans.org>
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On Sun, Oct 26, 2014 at 04:24:42PM +0100, Tijl Coosemans wrote: > Hi, > > I worked on AGP support for Radeon cards this week. Please take a look > at the attached patches. > > Patch 1: > Adds support for AGP_USER_TYPES to sys/dev/agp. For normal memory types > a vm_object is allocated, for user types only a vm_page array. It is > then up to the caller (e.g. TTM code) to manage this array. Arbitrary > pages can be mapped into the GTT this way. > Patch 3: > Enable AGP support in sys/dev/drm2. In PCI mode the GTT exists on the > graphics card so when accessing system memory it already does its own > virtual address translation and only physical addresses appear on the > system bus. The CPU can access the same addresses with its own VM > system like it always does. In AGP mode, translation is done by the > AGP chipset so fictitious addresses appear on the system bus. For the > CPU cache management to work correctly it needs to use these same > fictitious addresses instead of using the real physical addresses > directly. The patch marks the AGP aperture range fictitious in > radeon_device.c where the VRAM aperture is also marked fictitious such > that PHYS_TO_VM_PAGE in ttm_bo_vm_fault works for addresses in this > range. > > The rest of the patch is mostly porting to our agp_* API. It also > fixes two memory leaks in ttm_agp_backend.c. One is a missing free in > ttm_agp_tt_create. The other is because ttm_agp_bind allocates an > agp_memory struct but ttm_agp_unbind does not free it. So when calling > ttm_agp_bind a second time the reference to the struct is lost. The > patch changes ttm_agp_bind so the allocation only happens in the first > call. The struct is released in ttm_agp_destroy. Looking at the combination of patch 1 + 3. Do you really need to change the container for the AGP_USER_MEMORY ? Wouldn't it be enough to allocate array in ttm_agp_bind() and copy pointers to pages from the agp backing object to the array ?
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