Messages in this thread | | | Subject | Re: [PATCH] fbdev/omap: fix max fclk divider for omap36xx | From | Tomi Valkeinen <> | Date | Mon, 21 Oct 2019 11:44:21 +0300 |
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On 18/10/2019 16:05, 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-4.4.y only > > diff --git a/drivers/video/fbdev/omap2/dss/dss.c b/drivers/video/fbdev/omap2/dss/dss.c > index 9200a8668b49..a57c3a5f4bf8 100644 > --- a/drivers/video/fbdev/omap2/dss/dss.c > +++ b/drivers/video/fbdev/omap2/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, >
To clarify, this patch is only for the v4.4 stable, whereas the previous patch was for next merge window and v4.9+ stable. Right?
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Tomi
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