linux-kernel - Re: [PATCH v6 4/8] drm/msm/dp: avoid handling masked interrupts

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Date:   Thu, 31 Mar 2022 01:16:23 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Sankeerth Billakanti <quic_sbillaka@...cinc.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, robdclark@...il.com,
        seanpaul@...omium.org, swboyd@...omium.org,
        quic_kalyant@...cinc.com, quic_abhinavk@...cinc.com,
        dianders@...omium.org, quic_khsieh@...cinc.com,
        bjorn.andersson@...aro.org, sean@...rly.run, airlied@...ux.ie,
        daniel@...ll.ch, quic_vproddut@...cinc.com,
        quic_aravindh@...cinc.com
Subject: Re: [PATCH v6 4/8] drm/msm/dp: avoid handling masked interrupts

On Wed, 30 Mar 2022 at 19:03, Sankeerth Billakanti
<quic_sbillaka@...cinc.com> wrote:
>
> The interrupt register will still reflect the connect and disconnect
> interrupt status without generating an actual HW interrupt.
> The controller driver should not handle those masked interrupts.
>
> Signed-off-by: Sankeerth Billakanti <quic_sbillaka@...cinc.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_catalog.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
> index 3c16f95..1809ce2 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
> @@ -608,13 +608,14 @@ u32 dp_catalog_hpd_get_intr_status(struct dp_catalog *dp_catalog)
>  {
>         struct dp_catalog_private *catalog = container_of(dp_catalog,
>                                 struct dp_catalog_private, dp_catalog);
> -       int isr = 0;
> +       int isr, mask;
>
>         isr = dp_read_aux(catalog, REG_DP_DP_HPD_INT_STATUS);
>         dp_write_aux(catalog, REG_DP_DP_HPD_INT_ACK,
>                                  (isr & DP_DP_HPD_INT_MASK));
> +       mask = dp_read_aux(catalog, REG_DP_DP_HPD_INT_MASK);
>
> -       return isr;
> +       return isr & (DP_DP_HPD_STATE_STATUS_MASK | mask);

I suspect that the logic is inverted here. Shouldn't it be:

return isr & DP_DP_HPD_STATE_STATUS_MASK & mask;

?

>  }
>
>  int dp_catalog_ctrl_get_interrupt(struct dp_catalog *dp_catalog)
> --
> 2.7.4
>


-- 
With best wishes
Dmitry