On 3.1.2018 10:06, Mika Westerberg wrote: > 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 > Hi Mika,
The new kernel is installed and up and running. Still unable to save settings in BIOS. Leo -- 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
