Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20191018124938.29313-1-aford173@gmail.com> <7b8b6eba-2cb3-9b25-66e2-e128cc09ceb4@ti.com>
In-Reply-To: <7b8b6eba-2cb3-9b25-66e2-e128cc09ceb4@ti.com>
From:   Adam Ford <aford173@gmail.com>
Date:   Fri, 8 Nov 2019 07:09:31 -0600
Message-ID: <CAHCN7xJjX4jWhcRstJV02py0D4Wq_XHoWt9aHTxXANEOwdp+rg@mail.gmail.com>
Subject: Re: [PATCH] fbdev/omap: fix max fclk divider for omap36xx
To:     Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc:     linux-fbdev@vger.kernel.org,
        Linux-OMAP <linux-omap@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Adam Ford <adam.ford@logicpd.com>,
        stable <stable@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Oct 21, 2019 at 3:42 AM Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
>
> On 18/10/2019 15:49, Adam Ford wrote:
> > The OMAP36xx and AM/DM37x TRMs say that the maximum divider for DSS fclk
> > (in CM_CLKSEL_DSS) is 32. Experimentation shows that this is not
> > correct, and using divider of 32 breaks DSS with a flood or underflows
> > and sync losts. Dividers up to 31 seem to work fine.
> >
> > There is another patch to the DT files to limit the divider correctly,
> > but as the DSS driver also needs to know the maximum divider to be able
> > to iteratively find good rates, we also need to do the fix in the DSS
> > driver.
> >
> > Signed-off-by: Adam Ford <aford173@gmail.com>
> > Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > Cc: stable@vger.kernel.org #linux-4.9.y+
> >
> > diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > index 48c6500c24e1..4429ad37b64c 100644
> > --- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > +++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > @@ -843,7 +843,7 @@ static const struct dss_features omap34xx_dss_feats = {
> >   };
> >
> >   static const struct dss_features omap3630_dss_feats = {
> > -     .fck_div_max            =       32,
> > +     .fck_div_max            =       31,
> >       .dss_fck_multiplier     =       1,
> >       .parent_clk_name        =       "dpll4_ck",
> >       .dpi_select_source      =       &dss_dpi_select_source_omap2_omap3,
> >
>
> Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

What is the next step to get these integrated into 4.9+?

adam
>
>   Tomi
>
> --
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki