This bug is awaiting verification that the 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- hirsute' to 'verification-done-hirsute'. If the problem still exists, change the tag 'verification-needed-hirsute' to 'verification-failed- hirsute'.
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: verification-needed-hirsute -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-oem-5.13 in Ubuntu. https://bugs.launchpad.net/bugs/1936682 Title: Fix kernel panic caused by legacy devices on AMD platforms Status in HWE Next: New Status in linux package in Ubuntu: Confirmed Status in linux-oem-5.10 package in Ubuntu: Invalid Status in linux-oem-5.13 package in Ubuntu: Invalid Status in linux source package in Focal: Won't Fix Status in linux-oem-5.10 source package in Focal: Fix Released Status in linux-oem-5.13 source package in Focal: Fix Released Status in linux source package in Hirsute: Fix Committed Status in linux-oem-5.10 source package in Hirsute: Invalid Status in linux-oem-5.13 source package in Hirsute: Invalid Status in linux source package in Impish: Confirmed Status in linux-oem-5.10 source package in Impish: Invalid Status in linux-oem-5.13 source package in Impish: Invalid Bug description: [Impact] When a legacy device is only 32bit DMA capable and it's in the same IOMMU group with iommu_v2 capable devices, the device in question will be forced to use identity mapping and triggers kernel panic on DMA operation because it can't do 64bit DMA. [Fix] Keep swiotlb enabled so legacy devices can do 64bit DMA. This is also how Intel and ARM64 platforms deal with legacy devices. [Test] Boot an affected system. Kernel panic in Realtek WiFi driver's probe routine. After the patch is applied, the system can work normally. [Where problems could occur] The default swiotlb uses 64MB memory, so if the system doesn't have any legacy device, there are 64MB ram less for the system to use. To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1936682/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp