On 13/10/17 10:24 AM, Christian König wrote: > Am 13.10.2017 um 10:08 schrieb Michel Dänzer: >> On 12/10/17 07:54 PM, Harry Wentland wrote: >>> We're overflowing the last bit. Cast it explicitly >>> >>> Signed-off-by: Harry Wentland <harry.wentland at amd.com> >>> --- >>>  drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c | 2 +- >>>  1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c >>> b/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c >>> index cb94e18cc455..715dc789bb24 100644 >>> --- a/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c >>> +++ b/drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c >>> @@ -1047,7 +1047,7 @@ static enum bp_result >>> get_embedded_panel_info_v2_1( >>>          lvds->lcd_timing.miscinfo & ATOM_V_REPLICATIONBY2; >>>      info->lcd_timing.misc_info.COMPOSITE_SYNC = >>>          lvds->lcd_timing.miscinfo & ATOM_COMPOSITESYNC; >>> -   info->lcd_timing.misc_info.INTERLACE = >>> +   info->lcd_timing.misc_info.INTERLACE = (uint32_t) >>>          lvds->lcd_timing.miscinfo & ATOM_INTERLACE; >> I wasn't sure offhand, so I had to write a little test program, but it >> looks like this doesn't work as intended: (lvds->lcd_timing.miscinfo & >> ATOM_INTERLACE) is an unsigned 16-bit value, which is either 0x80 >> (ATOM_INTERLACE) or 0. Assigning that to the unsigned 1-bit field >> info->lcd_timing.misc_info.INTERLACE always results in 0. Casting the >> 16-bit value to 32 bits doesn't change that. I think what's intended >> here is something like info->lcd_timing.misc_info.INTERLACE = >> (lvds->lcd_timing.miscinfo & ATOM_INTERLACE) != 0; Looks like there's >> the same problem with other fields of info->lcd_timing.misc_info >> above. Another possible solution is making the fields of struct >> misc_info bool instead of uint32_t. > > While your approach works as well IIRC converting an arbitrary value > into a boolean is usually done with "!!". > > E.g. that should look like: > >    info->lcd_timing.misc_info.INTERLACE = >        !!(lvds->lcd_timing.miscinfo & ATOM_INTERLACE); Right, that works as well, thanks. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
