linux-kernel - Re: [PATCH v5 26/36] drm/bridge: analogix_dp: Properly disable aux chan retries on rockchip

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Date:   Wed, 14 Mar 2018 12:23:49 +0530
From:   Archit Taneja <architt@...eaurora.org>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        inki.dae@...sung.com, thierry.reding@...il.com, hjc@...k-chips.com,
        seanpaul@...omium.org, airlied@...ux.ie, tfiga@...omium.org,
        heiko@...ech.de
Cc:     dri-devel@...ts.freedesktop.org, dianders@...omium.org,
        a.hajda@...sung.com, ykk@...k-chips.com, kernel@...labora.com,
        m.szyprowski@...sung.com, linux-samsung-soc@...r.kernel.org,
        jy0922.shim@...sung.com, rydberg@...math.org, krzk@...nel.org,
        linux-rockchip@...ts.infradead.org, kgene@...nel.org,
        linux-input@...r.kernel.org, orjan.eide@....com,
        wxt@...k-chips.com, jeffy.chen@...k-chips.com,
        linux-arm-kernel@...ts.infradead.org, mark.yao@...k-chips.com,
        wzz@...k-chips.com, hl@...k-chips.com, jingoohan1@...il.com,
        sw0312.kim@...sung.com, linux-kernel@...r.kernel.org,
        kyungmin.park@...sung.com, Laurent.pinchart@...asonboard.com,
        kuankuan.y@...il.com, hshi@...omium.org,
        Stéphane Marchesin <marcheu@...omium.org>
Subject: Re: [PATCH v5 26/36] drm/bridge: analogix_dp: Properly disable aux
 chan retries on rockchip



On Saturday 10 March 2018 03:53 AM, Enric Balletbo i Serra wrote:
> From: Douglas Anderson <dianders@...omium.org>
> 
> The comments in analogix_dp_init_aux() claim that we're disabling aux
> channel retries, but then right below it for Rockchip it sets them to
> 3.  If we actually need 3 retries for Rockchip then we could adjust
> the comment, but it seems more likely that we want the same retry
> behavior across all platforms.

Reviewed-by: Archit Taneja <architt@...eaurora.org>

Thanks,
Archit

> 
> Cc: Stéphane Marchesin <marcheu@...omium.org>
> Cc: 征增 王 <wzz@...k-chips.com>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> Signed-off-by: Sean Paul <seanpaul@...omium.org>
> Signed-off-by: Thierry Escande <thierry.escande@...labora.com>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
> ---
> 
>   drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 15 ++++++++-------
>   1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> index 58e8a28e99aa..a5f2763d72e4 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> @@ -481,15 +481,16 @@ void analogix_dp_init_aux(struct analogix_dp_device *dp)
>   
>   	analogix_dp_reset_aux(dp);
>   
> -	/* Disable AUX transaction H/W retry */
> +	/* AUX_BIT_PERIOD_EXPECTED_DELAY doesn't apply to Rockchip IP */
>   	if (dp->plat_data && is_rockchip(dp->plat_data->dev_type))
> -		reg = AUX_BIT_PERIOD_EXPECTED_DELAY(0) |
> -		      AUX_HW_RETRY_COUNT_SEL(3) |
> -		      AUX_HW_RETRY_INTERVAL_600_MICROSECONDS;
> +		reg = 0;
>   	else
> -		reg = AUX_BIT_PERIOD_EXPECTED_DELAY(3) |
> -		      AUX_HW_RETRY_COUNT_SEL(0) |
> -		      AUX_HW_RETRY_INTERVAL_600_MICROSECONDS;
> +		reg = AUX_BIT_PERIOD_EXPECTED_DELAY(3);
> +
> +	/* Disable AUX transaction H/W retry */
> +	reg |= AUX_HW_RETRY_COUNT_SEL(0) |
> +	       AUX_HW_RETRY_INTERVAL_600_MICROSECONDS;
> +
>   	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_HW_RETRY_CTL);
>   
>   	/* Receive AUX Channel DEFER commands equal to DEFFER_COUNT*64 */
>