@@ -573,9 +573,17 @@ static int adv7511_get_modes(struct adv7511 *adv7511,
unsigned int count;
/* Reading the EDID only works if the device is powered */
- if (!adv7511->powered)
+ if (!adv7511->powered) {
+ unsigned int edid_i2c_addr =
+ (adv7511->i2c_main->addr << 1) + 4;
+
__adv7511_power_on(adv7511);
+ /* Reset the EDID_I2C_ADDR register as it might be cleared */
+ regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR,
+ edid_i2c_addr);
+ }
+
edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
if (!adv7511->powered)
I've found that by just turning the chip on and off via the POWER_DOWN register, I end up getting i2c_transfer errors on HiKey. Investigating further, it seems some of the register state in the regmap cache is getting lost, likely as the device registers were reset during power off. Thus this patch simply re-writes the i2c address to the ADV7511_REG_EDID_I2C_ADDR register to ensure its properly set before we try to read the EDID data. Cc: David Airlie <airlied@linux.ie> Cc: Archit Taneja <architt@codeaurora.org> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com> Cc: Lars-Peter Clausen <lars@metafoo.de> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz <john.stultz@linaro.org> --- v4: New approach to make the EDID_I2C_ADDR register sane, as suggested by Laurent --- drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) -- 2.7.4