Sorry about the delay but we wanted to make sure the proposed fix can recover the two test systems we have reliably before asking others to try it.
I've attached a patch to this bug that should fix the still affected systems. It applies on top of v4.15-rc6 and I'll be sending it upstream as well. Canonical already created a kernel package including the fix and it can be installed from the following link: http://people.canonical.com/~ypwong/lp1734147/linux- image-4.15.0-041500rc6-generic_4.15.0-041500rc6.201712312330+20170103+1_amd64.deb The reason why v4.14.9 which includes 9d63f17661e2 ("spi-nor: intel-spi: Fix broken software sequencing codes") recovers many systems but not all is because: - These systems have CMP=1 in the other status register (SR2) making the flash read-only (this is the symptom). - Linux SPI-NOR core clears status register properly for flash chips that have SPI_NOR_HAS_LOCK set. - Serial flashes automatically clear CMP and few other bits if 0 is written to the first status register using WRSR command. - In order to WRSR take effect the serial flash need to be write enabled (WREN must have been issued before WRSR at some point). - The systems that recovered the WREN was in effect (probably issued by the BIOS before handing off to the OS) so when Linux writes 0 to the status register CMP bit is also automatically cleared and the problem goes away. Those systems that were not recovered WREN was not in effect so clearing the status register and CMP bit was ignored by the serial flash chip. Normally WREN is send as a preopcode part of an atomic sequence when software sequencing is used. This has been enabled since commit 8c473dd61bb5 ("spi-nor: intel-spi: Don't assume OPMENU0/1 to be programmed by BIOS"). However, many systems have two write enable preopcodes available the PREOP_OPTYPE register: 0x50 - Write enable for volatile status register 0x06 - Write enable (WREN) The current code picks the former which does not enable write for non-volatile bits so any writes to the status register non-volatile bits, including BP0/1/2 protection bits do not take effect. The attached patch changes the driver so that it prefers WREN over other write enable preopcodes. Booting to the kernel with the patch applied on a system where the issue still persists should reset the protection bits and allow the BIOS to save settings again. ** Patch added: "0001-spi-nor-intel-spi-Prefer-WREN-over-other-write-enabl.patch" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1734147/+attachment/5030406/+files/0001-spi-nor-intel-spi-Prefer-WREN-over-other-write-enabl.patch -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734147 Title: Ubuntu 17.10 corrupting BIOS - many LENOVO laptops models To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1734147/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
