Public bug reported: [Impact] The memory region intel-lpss-pci uses has been declared as write-combining [ 0.001728] 5 base 4000000000 mask 6000000000 write-combining This leads to the system hangs up during booting up.
This is a BIOS issue, but there are some platforms on the market and users are struggling on booting up the machines. So, we may have to fix this in the kernel. [Fix] Tuowen Zhao(ztuo...@gmail.com)[1] provides a diff patch for intel-lpss driver to claim to use un-catchable memory while calling __devm_ioremap(), and it works well. To avoid the potential impact on other machines, I add a quirk to list the machines which has the write-combining area in MTRR which overlaps with the address that intel-lpss uses, only the machines in the list pass the DEVM_IOREMAP_UC to __devm_ioremap(). [Test] Verified on Dell XPS 13 7390 2-in-1 [Regression Potential] Low, without this patch, the machine even can't boot. And the quirk only for specific machines, so the modification won't affect other machines. 1. https://bugzilla.kernel.org/show_bug.cgi?id=203485#c23 ** Affects: linux (Ubuntu) Importance: Undecided Assignee: AceLan Kao (acelankao) Status: In Progress ** Affects: linux (Ubuntu Bionic) Importance: Undecided Assignee: AceLan Kao (acelankao) Status: In Progress ** Affects: linux (Ubuntu Disco) Importance: Undecided Assignee: AceLan Kao (acelankao) Status: In Progress ** Affects: linux (Ubuntu Eoan) Importance: Undecided Assignee: AceLan Kao (acelankao) Status: In Progress ** Affects: linux (Ubuntu Ff-series) Importance: Undecided Assignee: AceLan Kao (acelankao) Status: In Progress ** Also affects: linux (Ubuntu Ff-series) Importance: Undecided Status: New ** Also affects: linux (Ubuntu Bionic) Importance: Undecided Status: New ** Also affects: linux (Ubuntu Eoan) Importance: Undecided Status: New ** Also affects: linux (Ubuntu Disco) Importance: Undecided Status: New ** Changed in: linux (Ubuntu Bionic) Assignee: (unassigned) => AceLan Kao (acelankao) ** Changed in: linux (Ubuntu Disco) Assignee: (unassigned) => AceLan Kao (acelankao) ** Changed in: linux (Ubuntu Eoan) Assignee: (unassigned) => AceLan Kao (acelankao) ** Changed in: linux (Ubuntu Ff-series) Assignee: (unassigned) => AceLan Kao (acelankao) ** Changed in: linux (Ubuntu Bionic) Status: New => In Progress ** Changed in: linux (Ubuntu Disco) Status: New => In Progress ** Changed in: linux (Ubuntu Eoan) Status: New => In Progress ** Changed in: linux (Ubuntu Ff-series) Status: New => In Progress -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1845584 Title: intel-lpss driver conflicts with write-combining MTRR region Status in linux package in Ubuntu: In Progress Status in linux source package in Bionic: In Progress Status in linux source package in Disco: In Progress Status in linux source package in Eoan: In Progress Status in linux source package in FF-Series: In Progress Bug description: [Impact] The memory region intel-lpss-pci uses has been declared as write-combining [ 0.001728] 5 base 4000000000 mask 6000000000 write-combining This leads to the system hangs up during booting up. This is a BIOS issue, but there are some platforms on the market and users are struggling on booting up the machines. So, we may have to fix this in the kernel. [Fix] Tuowen Zhao(ztuo...@gmail.com)[1] provides a diff patch for intel-lpss driver to claim to use un-catchable memory while calling __devm_ioremap(), and it works well. To avoid the potential impact on other machines, I add a quirk to list the machines which has the write-combining area in MTRR which overlaps with the address that intel-lpss uses, only the machines in the list pass the DEVM_IOREMAP_UC to __devm_ioremap(). [Test] Verified on Dell XPS 13 7390 2-in-1 [Regression Potential] Low, without this patch, the machine even can't boot. And the quirk only for specific machines, so the modification won't affect other machines. 1. https://bugzilla.kernel.org/show_bug.cgi?id=203485#c23 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1845584/+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
