radv/video: Add low-latency flags

radv equivalent of 62f07b8c.

Reviewed-by: David Rosca <david.rosca@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40524>

docs/envvars.rst

@@ -1574,6 +1574,10 @@ RADV driver environment variables
       enable experimental implementation of VK_EXT_host_image_copy (GFX10+)
    ``localbos``
       enable local BOs
+   ``lowlatencydec``
+      Enable low latency decoding
+   ``lowlatencyenc``
+      Enable low latency encoding
    ``nggc``
       enable NGG culling for GFX11+
    ``nircache``

src/amd/vulkan/radv_debug.h

@@ -99,6 +99,8 @@ enum {
    RADV_PERFTEST_SPARSE = 1u << 17,
    RADV_PERFTEST_RT_CPS = 1u << 18,
    RADV_PERFTEST_BFLOAT16 = 1u << 19,
+   RADV_PERFTEST_LOWLATENCYDEC = 1u << 20,
+   RADV_PERFTEST_LOWLATENCYENC = 1u << 21,
 };
 
 enum {

src/amd/vulkan/radv_instance.c

@@ -124,6 +124,8 @@ static const struct debug_control radv_perftest_options[] = {
    {"sparse", RADV_PERFTEST_SPARSE},
    {"rtcps", RADV_PERFTEST_RT_CPS},
    {"bfloat16", RADV_PERFTEST_BFLOAT16},
+   {"lowlatencydec", RADV_PERFTEST_LOWLATENCYDEC},
+   {"lowlatencyenc", RADV_PERFTEST_LOWLATENCYENC},
    {NULL, 0},
 };
 

src/amd/vulkan/radv_video.c

@@ -2113,6 +2113,7 @@ radv_CmdDecodeVideoKHR(VkCommandBuffer commandBuffer, const VkVideoDecodeInfoKHR
       .width = frame_info->dstPictureResource.codedExtent.width,
       .height = frame_info->dstPictureResource.codedExtent.height,
       .tier = select_tier(device, vid, frame_info),
+      .low_latency = radv_physical_device_instance(pdev)->perftest_flags & RADV_PERFTEST_LOWLATENCYDEC,
    };
 
    if (vid->sessionctx.mem) {

src/amd/vulkan/radv_video_enc.c

@@ -1078,7 +1078,8 @@ radv_enc_latency(struct radv_cmd_buffer *cmd_buffer, VkVideoEncodeTuningModeKHR
    struct radv_device *device = radv_cmd_buffer_device(cmd_buffer);
    const struct radv_physical_device *pdev = radv_device_physical(device);
    const bool low_latency = tuning_mode == VK_VIDEO_ENCODE_TUNING_MODE_LOW_LATENCY_KHR ||
-                            tuning_mode == VK_VIDEO_ENCODE_TUNING_MODE_ULTRA_LOW_LATENCY_KHR;
+                            tuning_mode == VK_VIDEO_ENCODE_TUNING_MODE_ULTRA_LOW_LATENCY_KHR ||
+                            radv_physical_device_instance(pdev)->perftest_flags & RADV_PERFTEST_LOWLATENCYENC;
 
    RADEON_ENC_BEGIN(pdev->vcn_enc_cmds.enc_latency);
    RADEON_ENC_CS(low_latency ? 1000 : 0);