Commit 006388a8 authored by BALATON Zoltan's avatar BALATON Zoltan Committed by Gerd Hoffmann
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ati-vga: Fix GPIO_MONID register write 



Also update bitbang_i2c state when output bits are changed while
enable bits are set. This fixes EDID access by the ATI FCode ROM.

Signed-off-by: default avatarBALATON Zoltan <balaton@eik.bme.hu>
Message-id: 292e70a92b7fbfd9a4120d433dbdcfda4e5f6c3c.1565558093.git.balaton@eik.bme.hu
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
parent df1e4cf4

hw/display/ati.c

+7 −4
Original line number Diff line number Diff line
@@ -564,12 +564,15 @@ static void ati_mm_write(void *opaque, hwaddr addr, 
                               addr - GPIO_MONID, data, size);

            /*

             * Rage128p accesses DDC used to get EDID via these bits.

             * Only touch i2c when write overlaps 3rd byte because some

             * drivers access this reg via multiple partial writes and

             * without this spurious bits would be sent.

             * Because some drivers access this via multiple byte writes

             * we have to be careful when we send bits to avoid spurious

             * changes in bitbang_i2c state. So only do it when mask is set

             * and either the enable bits are changed or output bits changed

             * while enabled.

             */

            if ((s->regs.gpio_monid & BIT(25)) &&

                addr <= GPIO_MONID + 2 && addr + size > GPIO_MONID + 2) {

                ((addr <= GPIO_MONID + 2 && addr + size > GPIO_MONID + 2) ||

                 (addr == GPIO_MONID && (s->regs.gpio_monid & 0x60000)))) {

                s->regs.gpio_monid = ati_i2c(&s->bbi2c, s->regs.gpio_monid, 1);

            }

        }