Re: [PATCH v11 17/19] drm: bridge: analogix/dp: expand the look time for waiting AUX CH reply

[Yakir Yang]

Hi Jingoo,

On 12/23/2015 12:24 PM, Yakir Yang wrote:
> Hi Jingoo,
>
> On 12/22/2015 08:26 PM, Jingoo Han wrote:
> > On Wednesday, December 16, 2015 12:58 PM, Yakir Yang wrote:
> > > After test on rockchiop platform, i found sometims driver would failed
> > > at reading EDID message. After debugging more, i found that it's okay
> > > to read_a byte from i2c, but it would failed at AUX transcation if we
> > > try to ready multi-bytes from i2c.
> > >
> > > Driver just can't received the AUX CH reply command, even no AUX error
> > > code. I may guess that the AUX wait time is not enough, so I try to
> > > expand the AUX wait time, and i do see this could fix the EDID read
> > > failed at rockchip platform.
> > >
> > > And I thought that expand the wait time won't hurt Exynos platform too
> > > much, cause Exynos didn't have this problem, then driver would received
> > > the reply command very soon, so no more additional wait time would 
> > > bring
> > > to Exynos platform.
> > >
> > > Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
> > > ---
> > > Changes in v11: None
> > > Changes in v10: None
> > > Changes in v9: None
> > > Changes in v8: None
> > > Changes in v7: None
> > > Changes in v6: None
> > > Changes in v5: None
> > > Changes in v4: None
> > > Changes in v3: None
> > > Changes in v2: None
> > >
> > >   drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > > b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > > index c7e2959..dc376bd 100644
> > > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> > > @@ -482,7 +482,7 @@ int analogix_dp_start_aux_transaction(struct 
> > > analogix_dp_device *dp)
> > >       reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA);
> > >       while (!(reg & RPLY_RECEIV)) {
> > >           timeout_loop++;
> > > -        if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
> > > +        if (DP_TIMEOUT_LOOP_COUNT * 10 < timeout_loop) {
> > No, I hate this coding.
> > analogix_dp_reg.c is the common code that can be shared by various SoCs.
> > Please, find another way.
>
> Okay, I have double checked that i do have this problem in my side. 
> Hmmm.....
> I thought it's okay for you if I expand the "DP_TIMEOUT_LOOP_COUNT" 
> directly,
> it won't hurt Exynos platform too much, cause Exynos didn't have this 
> problem,
> then driver would received,the reply command very soon, so no more 
> additional
> wait time would bring to Exynos platform.

Oh, sorry, little mistaken, I mean, is it okay for you to expand the 
"DP_TIMEOUT_LOOP_COUNT" directly ?

- Yakir


> And actually the datasheet haven't described the spec of aux reply 
> delay time.
>
> Thanks,
> - Yakir
>
> > Best regards,
> > Jingoo Han
> >
> >
> > >               dev_err(dp->dev, "AUX CH command reply failed!\n");
> > >               return -ETIMEDOUT;
> > >           }
> > > --
> > > 1.9.1
>
>
>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/linux-rockchip


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