Fishy AMD Sienna CiChlid reference gets added to Linux driver patches, likely to be 'Big Navi' Navi 21
Recently, we have seen the names of several Navi 21 aka 'Big Navi' SKUs leak. Now, more evidence pointing towards Big Navi is available thanks to new AMD Radeon Linux Driver patches. Spotted by Phoronix, the new driver patches indicate a "Sienna CiChlid" GPU, which could very well be the RDNA2-based Big Navi.
About 207 patches pertaining to AMD Sienna CiChlid, which incidentally means yellowish-brown fish, were added to the Linux driver stack. According to the author Alex Deucher on Freedesktop.org,
Sienna Cichlid is a GPU from AMD. This patch set adds support for it including power management, display, kfd, interrupts, gfx, multi-media, etc. The new register headers are really big so I haven't sent them to the list. You can view the new patches including the register headers on the following git branch: https://cgit.freedesktop.org/~agd5f/linux/log/?h=amd-staging-drm-next-sienna_cichlid
That Sienna Cichlid could indeed be Navi 21 or Big Navi can be gleaned from the driver patches, which have the entry "amdgpu_amdkfd_gfx_v10.3.o". According to Videocardz, Navi GFX1030 is Navi 21 whereas GFX1010 and GFX1012 correspond to Navi 10 and Navi 14, respectively.
Another such indication comes from known leaker Komachi, who points out that Sienna CiChlid could indeed be Big Navi as the variant "40" indicated in the driver patches corresponds to another entry named "NV_NAVI21_P_A0 = 40".
This is the first time that we are seeing the Sienna CiChlid as a codename. Given that open source driver patches need to be released early, AMD seems to be using codenames that do not reveal much about their upcoming products.
Phoronix says that the new driver patches indicate new Video Core Next (VCN) 3.0 capabilities for video encoding and Display Core Next (DCN) 3.0 on the display front. Current Navi GPUs use VCN 2.0 and DCN 2.0, so we are likely looking at the next RDNA generation here.
An internal slide with an image of a fish also seems to have leaked detailing Sienna CiChlid's architecture. While we are not sure about the authenticity of the slide yet, it does suggest use of GDDR6 memory, dual-pipe GPC, two Async compute engines, VCN 3.0, DCN 3.0, and advanced clock and voltage control.
These new drivers, however, will not be integrated until the Linux 5.9 merge window opens in August and finally releases in October, which is the expected time of RDNA2 availability.