From mboxrd@z Thu Jan 1 00:00:00 1970 From: tomi.valkeinen@ti.com (Tomi Valkeinen) Date: Fri, 9 May 2014 10:38:54 +0300 Subject: [PATCH 1/4] OMAPDSS: Fix DSS clock multiplier issue on 3703 and probably 3630 In-Reply-To: <1398815562-24113-2-git-send-email-tony@atomide.com> References: <1398815562-24113-1-git-send-email-tony@atomide.com> <1398815562-24113-2-git-send-email-tony@atomide.com> Message-ID: <536C860E.1000501@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 30/04/14 02:52, Tony Lindgren wrote: > Otherwise we can get often errors like the following and the > display won't come on: > > omapdss APPLY error: FIFO UNDERFLOW on gfx, disabling the overlay > omapdss APPLY error: SYNC_LOST on channel lcd, restarting > the output with video overlays disabled > > There are some earlier references to this issue: > > http://www.spinics.net/lists/linux-omap/msg59511.html > http://www.spinics.net/lists/linux-omap/msg59724.html Those don't sound like the same issue, but it's hard to say. What kind of clock rates do you get? Cat you paste debugfs/omapdss/clk, with and without this patch? What resolution do you have? If it's a very high resolution (say, DVI output to a monitor), it could just be an issue of not-enough-memory-bandwidth. > It seems that it's safe to set the lower values even for 3630. > If we can confirm that 3630 works with the higher values > reliably we can add further detection. > > Signed-off-by: Tony Lindgren > --- > drivers/video/fbdev/omap2/dss/dss.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/video/fbdev/omap2/dss/dss.c b/drivers/video/fbdev/omap2/dss/dss.c > index d55266c..ad6561f 100644 > --- a/drivers/video/fbdev/omap2/dss/dss.c > +++ b/drivers/video/fbdev/omap2/dss/dss.c > @@ -707,9 +707,10 @@ static const struct dss_features omap34xx_dss_feats __initconst = { > .dpi_select_source = &dss_dpi_select_source_omap2_omap3, > }; > > +/* Supposedly 3630 can use div 32 mult 2, but that needs to be rechecked */ > static const struct dss_features omap3630_dss_feats __initconst = { > - .fck_div_max = 32, > - .dss_fck_multiplier = 1, > + .fck_div_max = 16, > + .dss_fck_multiplier = 2, These values tell about the clock hardware, they are not settings that can be changed to change the clock. OMAP3630 has a fixed x2 multiplier and a divider with maximum value of 16. Tomi -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: OpenPGP digital signature URL: