From: Mika Westerberg Date: Fri, 28 Jul 2017 10:50:42 +0000 (+0300) Subject: mfd: lpc_ich: Do not touch SPI-NOR write protection bit on Haswell/Broadwell X-Git-Tag: v4.14-rc1~110^2~13 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d9018976cdb6eefc62a7ba79a405f6c9661b08a7;p=platform%2Fkernel%2Flinux-exynos.git mfd: lpc_ich: Do not touch SPI-NOR write protection bit on Haswell/Broadwell 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 Signed-off-by: Mika Westerberg Signed-off-by: Lee Jones --- diff --git a/drivers/mfd/lpc_ich.c b/drivers/mfd/lpc_ich.c index 773f155..450ae36 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;