On Fri, 28 Jul 2017, Mika Westerberg wrote:
> At least on Lenovo Thinkpad Yoga, the BIOS seems to monitor the SPI-NOR
> write protection bit and if it is flipped to read/write it assumes the
> BIOS configuration was changed on next reboot. It then, for unknown
> reasons, resets the BIOS settings back to default.
>
> We can prevent this by just leaving the write protection bit intact and
> let the SPI-NOR driver know whether the device is writable or not. In
> case of this particular Lenovo the SPI-NOR flash will be exposed as
> read-only.
>
> Fixes: ff00d7a32a1b ("mfd: lpc_ich: Add support for SPI serial flash host
> controller")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=195951
> Reported-by: Abdó Roig-Marange <abdo.r...@gmail.com>
> Signed-off-by: Mika Westerberg <mika.westerb...@linux.intel.com>
> ---
> drivers/mfd/lpc_ich.c | 10 ----------
> 1 file changed, 10 deletions(-)
Applied, thanks.
> diff --git a/drivers/mfd/lpc_ich.c b/drivers/mfd/lpc_ich.c
> index 773f1554d2f9..450ae36645aa 100644
> --- a/drivers/mfd/lpc_ich.c
> +++ b/drivers/mfd/lpc_ich.c
> @@ -1119,17 +1119,7 @@ static int lpc_ich_init_spi(struct pci_dev *dev)
> res->start = spi_base + SPIBASE_LPT;
> res->end = res->start + SPIBASE_LPT_SZ - 1;
>
> - /*
> - * Try to make the flash chip writeable now by
> - * setting BCR_WPD. It it fails we tell the driver
> - * that it can only read the chip.
> - */
> pci_read_config_dword(dev, BCR, &bcr);
> - if (!(bcr & BCR_WPD)) {
> - bcr |= BCR_WPD;
> - pci_write_config_dword(dev, BCR, bcr);
> - pci_read_config_dword(dev, BCR, &bcr);
> - }
> info->writeable = !!(bcr & BCR_WPD);
> }
> break;
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
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