[PATCH 4.4.y] drm: adv7511: Re-write the i2c address before EDID probing

[PATCH 4.4.y] drm: adv7511: Re-write the i2c address before EDID probing

[Nhan Nguyen]

commit 3587c856675c45809010c2cee5b21096f6e8e938 upstream.

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 turns out that some of the register
state in hardware is getting lost, as the device registers are
reset when the chip is powered down.

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
Cc: stable@vger.kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Thong Ho <thong.ho.px@rvc.renesas.com>
Signed-off-by: Nhan Nguyen <nhan.nguyen.yb@renesas.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1484614372-15342-7-git-send-email-john.stultz@linaro.org
---
 drivers/gpu/drm/i2c/adv7511.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i2c/adv7511.c b/drivers/gpu/drm/i2c/adv7511.c
index ebb0fc8..dba5c0e 100644
--- a/drivers/gpu/drm/i2c/adv7511.c
+++ b/drivers/gpu/drm/i2c/adv7511.c
@@ -51,6 +51,10 @@ struct adv7511 {
 	struct gpio_desc *gpio_pd;
 };
 
+static const int edid_i2c_addr = 0x7e;
+static const int packet_i2c_addr = 0x70;
+static const int cec_i2c_addr = 0x78;
+
 static struct adv7511 *encoder_to_adv7511(struct drm_encoder *encoder)
 {
 	return to_encoder_slave(encoder)->slave_priv;
@@ -606,6 +610,9 @@ static int adv7511_get_modes(struct drm_encoder *encoder,
 				     ADV7511_INT1_DDC_ERROR);
 		}
 		adv7511->current_edid_segment = -1;
+		/* 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);
@@ -881,10 +888,6 @@ static int adv7511_parse_dt(struct device_node *np,
 	return 0;
 }
 
-static const int edid_i2c_addr = 0x7e;
-static const int packet_i2c_addr = 0x70;
-static const int cec_i2c_addr = 0x78;
-
 static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
 {
 	struct adv7511_link_config link_config;
-- 
1.9.1

Re: [PATCH 4.4.y] drm: adv7511: Re-write the i2c address before EDID probing

[Greg KH]

On Fri, Sep 08, 2017 at 09:46:02AM +0700, Nhan Nguyen wrote:
> commit 3587c856675c45809010c2cee5b21096f6e8e938 upstream.
> 
> 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 turns out that some of the register
> state in hardware is getting lost, as the device registers are
> reset when the chip is powered down.
> 
> 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
> Cc: stable@vger.kernel.org
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> Signed-off-by: Archit Taneja <architt@codeaurora.org>
> Signed-off-by: Thong Ho <thong.ho.px@rvc.renesas.com>
> Signed-off-by: Nhan Nguyen <nhan.nguyen.yb@renesas.com>
> Link: http://patchwork.freedesktop.org/patch/msgid/1484614372-15342-7-git-send-email-john.stultz@linaro.org
> ---
>  drivers/gpu/drm/i2c/adv7511.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)

Can you provide a working backport for the 4.9-stable kernel as well?

Also, please do not send backports for patches that do not also work in
newer stable kernels, like 4.9, I backported some of this series there,
but I shouldn't have to check for you.

thanks,

greg k-h

Re: [PATCH 4.4.y] drm: adv7511: Re-write the i2c address before EDID probing

[Nhan Ngoc. Nguyen]

This patch is ported from linux stable 4.9, commit 3587c856675c45809010c2cee5b21096f6e8e938.
So I think I don't need to port on version 4.9.

On 9/8/2017 2:21 PM, Greg KH wrote:
> On Fri, Sep 08, 2017 at 09:46:02AM +0700, Nhan Nguyen wrote:
>> commit 3587c856675c45809010c2cee5b21096f6e8e938 upstream.
>>
>> 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 turns out that some of the register
>> state in hardware is getting lost, as the device registers are
>> reset when the chip is powered down.
>>
>> 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
>> Cc: stable@vger.kernel.org
>> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>> Signed-off-by: John Stultz <john.stultz@linaro.org>
>> Signed-off-by: Archit Taneja <architt@codeaurora.org>
>> Signed-off-by: Thong Ho <thong.ho.px@rvc.renesas.com>
>> Signed-off-by: Nhan Nguyen <nhan.nguyen.yb@renesas.com>
>> Link: http://patchwork.freedesktop.org/patch/msgid/1484614372-15342-7-git-send-email-john.stultz@linaro.org
>> ---
>>   drivers/gpu/drm/i2c/adv7511.c | 11 +++++++----
>>   1 file changed, 7 insertions(+), 4 deletions(-)
> Can you provide a working backport for the 4.9-stable kernel as well?
>
> Also, please do not send backports for patches that do not also work in
> newer stable kernels, like 4.9, I backported some of this series there,
> but I shouldn't have to check for you.
>
> thanks,
>
> greg k-h

Re: [PATCH 4.4.y] drm: adv7511: Re-write the i2c address before EDID probing

[Greg KH]

On Fri, Sep 08, 2017 at 06:22:02PM +0700, Nhan Ngoc. Nguyen wrote:
> This patch is ported from linux stable 4.9, commit 3587c856675c45809010c2cee5b21096f6e8e938.

No, commit 3587c856675c45809010c2cee5b21096f6e8e938 showed up in
4.11-rc1:
	$ git describe --contains 3587c856675c45809010c2cee5b21096f6e8e938
	v4.11-rc1~83^2~38^2~2

> So I think I don't need to port on version 4.9.

I think it is still needed there...

And please do not top-post...

greg k-h