[Mesa-dev] [PATCH v3 1/2] nouveau: support for custom VRAM domains

[Alexandre Courbot]

Some GPUs (e.g. GK20A, GM20B) do not embed VRAM of their own and use
the system memory as a backend instead. For such systems, allocating
objects in VRAM results in errors since the kernel will not allow
VRAM objects allocations.

This patch adds a vram_domain member to struct nouveau_screen that can
optionally be initialized to an alternative domain to use for VRAM
allocations. If left untouched, NOUVEAU_BO_VRAM will be used for
systems that embed VRAM, and NOUVEAU_BO_GART will be used for VRAM-less
systems.

Code that uses GPU objects is then expected to use the NV_VRAM_DOMAIN()
macro in place of NOUVEAU_BO_VRAM to ensure correct behavior on
VRAM-less chips.

Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
 src/gallium/drivers/nouveau/nouveau_screen.c | 10 ++++++++++
 src/gallium/drivers/nouveau/nouveau_screen.h |  4 ++++
 2 files changed, 14 insertions(+)

diff --git a/src/gallium/drivers/nouveau/nouveau_screen.c b/src/gallium/drivers/nouveau/nouveau_screen.c
index b4f1413fd8ba..c6e5074db195 100644
--- a/src/gallium/drivers/nouveau/nouveau_screen.c
+++ b/src/gallium/drivers/nouveau/nouveau_screen.c
@@ -164,6 +164,16 @@ nouveau_screen_init(struct nouveau_screen *screen, struct nouveau_device *dev)
 		size = sizeof(nvc0_data);
 	}
 
+	/*
+	 * Set default VRAM domain if not overridden
+	 */
+	if (!screen->vram_domain) {
+		if (dev->vram_size > 0)
+			screen->vram_domain = NOUVEAU_BO_VRAM;
+		else
+			screen->vram_domain = NOUVEAU_BO_GART;
+	}
+
 	ret = nouveau_object_new(&dev->object, 0, NOUVEAU_FIFO_CHANNEL_CLASS,
 				 data, size, &screen->channel);
 	if (ret)
diff --git a/src/gallium/drivers/nouveau/nouveau_screen.h b/src/gallium/drivers/nouveau/nouveau_screen.h
index cf06f7e88aa0..30041b271c94 100644
--- a/src/gallium/drivers/nouveau/nouveau_screen.h
+++ b/src/gallium/drivers/nouveau/nouveau_screen.h
@@ -51,6 +51,8 @@ struct nouveau_screen {
 
 	boolean hint_buf_keep_sysmem_copy;
 
+	unsigned vram_domain;
+
 	struct {
 		unsigned profiles_checked;
 		unsigned profiles_present;
@@ -94,6 +96,8 @@ struct nouveau_screen {
 #endif
 };
 
+#define NV_VRAM_DOMAIN(screen) ((screen)->vram_domain)
+
 #ifdef NOUVEAU_ENABLE_DRIVER_STATISTICS
 # define NOUVEAU_DRV_STAT(s, n, v) do {         \
       (s)->stats.named.n += (v);               \
-- 
2.4.4