On 24/08/15 22:37, Ondrej Zary wrote:
> According to X.Org driver, chips older than TGUI9660 have only 1 width bit
> in AddColReg. Touching the 2nd one causes I2C/DDC to fail on TGUI9440.
>
> Set only 1 bit of width in AddColReg on TGUI9440 and CYBER9320.
>
> Signed-off-by: Ondrej Zary <li...@rainbow-software.org>
> ---
> drivers/video/fbdev/tridentfb.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/fbdev/tridentfb.c b/drivers/video/fbdev/tridentfb.c
> index 7429713..01b43e9 100644
> --- a/drivers/video/fbdev/tridentfb.c
> +++ b/drivers/video/fbdev/tridentfb.c
> @@ -673,8 +673,14 @@ static int get_nativex(struct tridentfb_par *par)
> static inline void set_lwidth(struct tridentfb_par *par, int width)
> {
> write3X4(par, VGA_CRTC_OFFSET, width & 0xFF);
> - write3X4(par, AddColReg,
> - (read3X4(par, AddColReg) & 0xCF) | ((width & 0x300) >> 4));
> + /* chips older than TGUI9660 have only 1 width bit in AddColReg */
> + /* touching the other one breaks I2C/DDC */
> + if (par->chip_id == TGUI9440 || par->chip_id == CYBER9320)
> + write3X4(par, AddColReg,
> + (read3X4(par, AddColReg) & 0xEF) | ((width & 0x100) >> 4));
> + else
> + write3X4(par, AddColReg,
> + (read3X4(par, AddColReg) & 0xCF) | ((width & 0x300) >> 4));
> }
>
> /* For resolutions smaller than FP resolution stretch */
> Thanks, queued for 4.3 fixes. Tomi
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