From: Yifeng Li tomli@tomli.me
commit 5481115e25e42b9215f2619452aa99c95f08492f upstream.
On a Thinkpad s30 (Pentium III / i440MX, Lynx3DM), rebooting with sm712fb framebuffer driver would cause the role of brightness up/down button to swap.
Experiments showed the FPR30 register caused this behavior. Moreover, even if this register don't have side-effect on other systems, over- writing it is also highly questionable, since it was originally configurated by the motherboard manufacturer by hardwiring pull-down resistors to indicate the type of LCD panel. We should not mess with it.
Stop writing to the SR30 (a.k.a FPR30) register.
Signed-off-by: Yifeng Li tomli@tomli.me Tested-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Cc: Teddy Wang teddy.wang@siliconmotion.com Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Bartlomiej Zolnierkiewicz b.zolnierkie@samsung.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/video/fbdev/sm712fb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -1144,8 +1144,8 @@ static void sm7xx_set_timing(struct smtc
/* init SEQ register SR30 - SR75 */ for (i = 0; i < SIZE_SR30_SR75; i++) - if ((i + 0x30) != 0x62 && (i + 0x30) != 0x6a && - (i + 0x30) != 0x6b) + if ((i + 0x30) != 0x30 && (i + 0x30) != 0x62 && + (i + 0x30) != 0x6a && (i + 0x30) != 0x6b) smtc_seqw(i + 0x30, vgamode[j].init_sr30_sr75[i]);