| Message ID | 1484608611-10956-1-git-send-email-john.stultz@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi John, Thank you for the patch. On Monday 16 Jan 2017 15:16:51 John Stultz wrote: > Laurent: Would something like the following be preferred? Seems > to work as well for me.. That looks good to me. Feel free to still de-duplicate the power on/off code if you want (but of course without adding the regcache_sync to the common power on function this time). Please see below for an additional comment. > 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 somehow 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> > --- > drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 405e460..32c59cb > 100644 > --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > @@ -567,6 +567,8 @@ static int adv7511_get_modes(struct adv7511 *adv7511, > > /* Reading the EDID only works if the device is powered */ > if (!adv7511->powered) { > + unsigned int edid_i2c_addr = (adv7511->i2c_main->addr << 1) + 4; > + > regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER, > ADV7511_POWER_POWER_DOWN, 0); > if (adv7511->i2c_main->irq) { > @@ -576,6 +578,9 @@ static int adv7511_get_modes(struct adv7511 *adv7511, > ADV7511_INT1_DDC_ERROR); > } > adv7511->current_edid_segment = -1; > + > + /* Reset the EDID_I2C_ADDR register as it may have been cleared */ > + regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR, edid_i2c_addr); As powering the device off called regcache_mark_dirty(), this will perform an I2C write and cache the value. If we then try to read the EDID a second time without going through a full power on/off sequence, I believe that regmap will skip the write the second time, as the cache will contain the same value and won't be marked as dirty. Should we call regcache_mark_dirty() when powering the device down further down this function ? > } > > edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
On Mon, Jan 16, 2017 at 3:36 PM, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > Hi John, > > Thank you for the patch. > > On Monday 16 Jan 2017 15:16:51 John Stultz wrote: >> Laurent: Would something like the following be preferred? Seems >> to work as well for me.. > > That looks good to me. Feel free to still de-duplicate the power on/off code > if you want (but of course without adding the regcache_sync to the common > power on function this time). Ok. Will do that. Thanks again for the feedback/direction here! >> @@ -576,6 +578,9 @@ static int adv7511_get_modes(struct adv7511 *adv7511, >> ADV7511_INT1_DDC_ERROR); >> } >> adv7511->current_edid_segment = -1; >> + >> + /* Reset the EDID_I2C_ADDR register as it may have been > cleared */ >> + regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR, > edid_i2c_addr); > > As powering the device off called regcache_mark_dirty(), this will perform an > I2C write and cache the value. If we then try to read the EDID a second time > without going through a full power on/off sequence, I believe that regmap will > skip the write the second time, as the cache will contain the same value and > won't be marked as dirty. Should we call regcache_mark_dirty() when powering > the device down further down this function ? Ah. Right. I had this in my earlier attempt, but thought I was simplifying things here. I'll correct this in the next revision. Thanks again! -john
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 405e460..32c59cb 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c @@ -567,6 +567,8 @@ static int adv7511_get_modes(struct adv7511 *adv7511, /* Reading the EDID only works if the device is powered */ if (!adv7511->powered) { + unsigned int edid_i2c_addr = (adv7511->i2c_main->addr << 1) + 4; + regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER, ADV7511_POWER_POWER_DOWN, 0); if (adv7511->i2c_main->irq) { @@ -576,6 +578,9 @@ static int adv7511_get_modes(struct adv7511 *adv7511, ADV7511_INT1_DDC_ERROR); } adv7511->current_edid_segment = -1; + + /* Reset the EDID_I2C_ADDR register as it may have been cleared */ + regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR, edid_i2c_addr); } edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
Laurent: Would something like the following be preferred? Seems to work as well for me.. thanks -john 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 somehow 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> --- drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 5 +++++ 1 file changed, 5 insertions(+)