Description of problem: This is a recurring boot-time problem between at least Fedora 19 and now Fedora 23 on SuperMicro X10DrI motherboards. I am not an expert but I believe this bug impacts direct cache accesses (DCA) and it seems to slow my Intel 2P server significantly. I have previously reported this under bug numbers 1185660 (Fedora 20) and 1185663 (Fedora 21). These were closed due to lack of details (my fault). Reproduction is easy as the error occurs during each boot. Additional info: reporter: libreport-2.6.3 WARNING: CPU: 0 PID: 355 at drivers/dma/ioat/dca.c:694 ioat3_dca_init+0x188/0x1a5 [ioatdma]() ioatdma 0000:00:04.0: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA Modules linked in: edac_core(+) mei(+) i2c_i801(+) lpc_ich(+) pcc_cpufreq(-) ioatdma(+) wmi shpchp ipmi_si(+) tpm_tis ipmi_msghandler tpm acpi_pad acpi_power_meter ast drm_kms_helper ttm drm igb ptp pps_core dca i2c_algo_bit CPU: 0 PID: 355 Comm: kworker/0:1 Not tainted 4.2.3-300.fc23.x86_64 #1 Hardware name: Supermicro X10DRi/X10DRi, BIOS 1.0b 09/17/2014 Workqueue: events work_for_cpu_fn 0000000000000000 00000000b9ab9214 ffff88085af23c08 ffffffff81771fca 0000000000000000 ffff88085af23c60 ffff88085af23c48 ffffffff8109e4a6 ffff88085a137160 ffff88105b337000 ffff88105b318650 ffff880858004200 Call Trace: [<ffffffff81771fca>] dump_stack+0x45/0x57 [<ffffffff8109e4a6>] warn_slowpath_common+0x86/0xc0 [<ffffffff8109e59e>] warn_slowpath_fmt_taint+0x4e/0x70 [<ffffffffa000e3a1>] ? alloc_dca_provider+0x21/0x40 [dca] [<ffffffffa018a9a8>] ioat3_dca_init+0x188/0x1a5 [ioatdma] [<ffffffffa0189e45>] ioat3_dma_probe+0x3a5/0x430 [ioatdma] [<ffffffffa018218b>] ioat_pci_probe+0x11b/0x1a0 [ioatdma] [<ffffffff813e6055>] local_pci_probe+0x45/0xa0 [<ffffffff810b3118>] work_for_cpu_fn+0x18/0x30 [<ffffffff810b64fe>] process_one_work+0x19e/0x3f0 [<ffffffff810b68fe>] worker_thread+0x1ae/0x450 [<ffffffff810b6750>] ? process_one_work+0x3f0/0x3f0 [<ffffffff810b6750>] ? process_one_work+0x3f0/0x3f0 [<ffffffff810bc8a8>] kthread+0xd8/0xf0 [<ffffffff810bc7d0>] ? kthread_worker_fn+0x160/0x160 [<ffffffff81778d9f>] ret_from_fork+0x3f/0x70 [<ffffffff810bc7d0>] ? kthread_worker_fn+0x160/0x160 Potential duplicate: bug 1185660
Created attachment 1090785 [details] File: dmesg
*********** MASS BUG UPDATE ************** We apologize for the inconvenience. There is a large number of bugs to go through and several of them have gone stale. Due to this, we are doing a mass bug update across all of the Fedora 23 kernel bugs. Fedora 23 has now been rebased to 4.7.4-100.fc23. Please test this kernel update (or newer) and let us know if you issue has been resolved or if it is still present with the newer kernel. If you have moved on to Fedora 24 or 25, and are still experiencing this issue, please change the version to Fedora 24 or 25. If you experience different issues, please open a new bug report for those.
Laura, I read your comments in bug nr 1309552 and I believe my DCA error to be similar to this reported BIOS bug. I understand this is probably not fixable except by a BIOS change and recommend this can be closed and you can move to another bug. Thanks for letting us know!