[PATCH v2 1/1] drm/amdgpu: Enable scatter gather display support

[Samuel Li]

It's auto by default. For CZ/ST, auto setting enables sg display
when vram size is small; otherwise still uses vram.
This patch fixed some potential hang issue introduced by change
"allow framebuffer in GART memory as well" due to CZ/ST hardware
limitation.

v2: Change default setting to auto, also some misc changes.
Signed-off-by: Samuel Li <Samuel.Li at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h               |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.c       | 10 ++++++++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.h       |  2 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c           |  4 ++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c            |  2 ++
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  3 ++-
 6 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index a7e2229..c942362 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -129,6 +129,7 @@ extern int amdgpu_lbpw;
 extern int amdgpu_compute_multipipe;
 extern int amdgpu_gpu_recovery;
 extern int amdgpu_emu_mode;
+extern int amdgpu_sg_display;
 
 #ifdef CONFIG_DRM_AMDGPU_SI
 extern int amdgpu_si_support;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
index 5495b29..1e7b950 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -513,8 +513,14 @@ uint32_t amdgpu_display_framebuffer_domains(struct amdgpu_device *adev)
 #if defined(CONFIG_DRM_AMD_DC)
 	if (adev->asic_type >= CHIP_CARRIZO && adev->asic_type < CHIP_RAVEN &&
 	    adev->flags & AMD_IS_APU &&
-	    amdgpu_device_asic_has_dc_support(adev->asic_type))
-		domain |= AMDGPU_GEM_DOMAIN_GTT;
+	    amdgpu_device_asic_has_dc_support(adev->asic_type)) {
+		if (amdgpu_sg_display == 1)
+			domain = AMDGPU_GEM_DOMAIN_GTT;
+		else if (amdgpu_sg_display == -1) {
+			if (adev->gmc.real_vram_size < AMDGPU_SG_THRESHOLD)
+				domain = AMDGPU_GEM_DOMAIN_GTT;
+		}
+	}
 #endif
 
 	return domain;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
index 2b11d80..2b25393 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.h
@@ -23,6 +23,8 @@
 #ifndef __AMDGPU_DISPLAY_H__
 #define __AMDGPU_DISPLAY_H__
 
+#define AMDGPU_SG_THRESHOLD  (256*1024*1024)
+
 uint32_t amdgpu_display_framebuffer_domains(struct amdgpu_device *adev);
 struct drm_framebuffer *
 amdgpu_display_user_framebuffer_create(struct drm_device *dev,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 1bfce79..19f11a5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -132,6 +132,7 @@ int amdgpu_lbpw = -1;
 int amdgpu_compute_multipipe = -1;
 int amdgpu_gpu_recovery = -1; /* auto */
 int amdgpu_emu_mode = 0;
+int amdgpu_sg_display = -1;
 
 MODULE_PARM_DESC(vramlimit, "Restrict VRAM for testing, in megabytes");
 module_param_named(vramlimit, amdgpu_vram_limit, int, 0600);
@@ -290,6 +291,9 @@ module_param_named(gpu_recovery, amdgpu_gpu_recovery, int, 0444);
 MODULE_PARM_DESC(emu_mode, "Emulation mode, (1 = enable, 0 = disable)");
 module_param_named(emu_mode, amdgpu_emu_mode, int, 0444);
 
+MODULE_PARM_DESC(sg_display, "Enable scatter gather display, (1 = enable, 0 = disable, -1 = auto");
+module_param_named(sg_display, amdgpu_sg_display, int, 0444);
+
 #ifdef CONFIG_DRM_AMDGPU_SI
 
 #if defined(CONFIG_DRM_RADEON) || defined(CONFIG_DRM_RADEON_MODULE)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
index 1206301..f57c355 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
@@ -138,6 +138,8 @@ static int amdgpufb_create_pinned_object(struct amdgpu_fbdev *rfbdev,
 	mode_cmd->pitches[0] = amdgpu_align_pitch(adev, mode_cmd->width, cpp,
 						  fb_tiled);
 	domain = amdgpu_display_framebuffer_domains(adev);
+	if (domain & AMDGPU_GEM_DOMAIN_GTT)
+		DRM_DEBUG_DRIVER("Scatter gather display: enabled\n");
 
 	height = ALIGN(mode_cmd->height, 8);
 	size = mode_cmd->pitches[0] * height;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 68ab325..7e9f247 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3074,7 +3074,8 @@ static int dm_plane_helper_prepare_fb(struct drm_plane *plane,
 		domain = AMDGPU_GEM_DOMAIN_VRAM;
 
 	r = amdgpu_bo_pin(rbo, domain, &afb->address);
-
+	rbo->preferred_domains = domain;
+	rbo->allowed_domains = domain;
 	amdgpu_bo_unreserve(rbo);
 
 	if (unlikely(r != 0)) {
-- 
2.7.4