This bug is awaiting verification that the linux-nvidia/6.8.0-1011.11 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-nvidia' to 'verification-done- noble-linux-nvidia'. If the problem still exists, change the tag 'verification-needed-noble-linux-nvidia' to 'verification-failed-noble- linux-nvidia'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: kernel-spammed-noble-linux-nvidia-v2 verification-needed-noble-linux-nvidia -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-nvidia in Ubuntu. https://bugs.launchpad.net/bugs/2071655 Title: PR for: "IB/mlx5: Use __iowrite64_copy() for write combining stores" Status in linux-nvidia package in Ubuntu: New Bug description: mlx5 has a built in self-test at driver startup to evaluate if the platform supports write combining to generate a 64 byte PCIe TLP or not. This has proven necessary because a lot of common scenarios end up with broken write combining (especially inside virtual machines) and there is other way to learn this information. This self test has been consistently failing on new ARM64 CPU designs (specifically with NVIDIA Grace's implementation of Neoverse V2). The C loop around writeq() generates some pretty terrible ARM64 assembly, but historically this has worked on a lot of existing ARM64 CPUs till now. We see it succeed about 1 time in 10,000 on the worst effected systems. The CPU architects speculate that the load instructions interspersed with the stores makes the WC buffers statistically flush too often and thus the generation of large TLPs becomes infrequent. This makes the boot up test unreliable in that it indicates no write-combining, however userspace would be fine since it uses a ST4 instruction. Further, S390 has similar issues where only the special zpci_memcpy_toio() will actually generate large TLPs, and the open coded loop does not trigger it at all. Fix both ARM64 and S390 by switching to __iowrite64_copy() which now provides architecture specific variants that have a high change of generating a large TLP with write combining. x86 continues to use a similar writeq loop in the generate __iowrite64_copy(). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-nvidia/+bug/2071655/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
