From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH 1/4] OMAPDSS: Fix DSS clock multiplier issue on 3703 and probably 3630 Date: Thu, 8 May 2014 16:20:07 -0700 Message-ID: <20140508232006.GG2198@atomide.com> References: <1398815562-24113-1-git-send-email-tony@atomide.com> <1398815562-24113-2-git-send-email-tony@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1398815562-24113-2-git-send-email-tony@atomide.com> Sender: linux-omap-owner@vger.kernel.org To: linux-arm-kernel@lists.infradead.org, linux-fbdev@vger.kernel.org, devicetree@vger.kernel.org, linux-omap@vger.kernel.org Cc: tomi.valkeinen@ti.com List-Id: devicetree@vger.kernel.org * Tony Lindgren [140429 16:53]: > 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 > > 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. BTW, I'm also seeing this warning on 3730-evm it may be related: [ 3.523101] ------------[ cut here ]------------ [ 3.528015] WARNING: CPU: 0 PID: 6 at drivers/video/fbdev/omap2/dss/dss.c:483 dss_set_fck_rate+0x6c/0x8c() [ 3.538360] clk rate mismatch: 108000000 != 115200000 [ 3.543518] Modules linked in: [ 3.546966] CPU: 0 PID: 6 Comm: kworker/u2:0 Tainted: G W 3.15.0-rc3-00015-gaa296fa-dirty #391 [ 3.557159] Workqueue: deferwq deferred_probe_work_func [ 3.562774] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [ 3.571014] [] (show_stack) from [] (dump_stack+0x80/0x9c) [ 3.578704] [] (dump_stack) from [] (warn_slowpath_common+0x68/0x8c) [ 3.587249] [] (warn_slowpath_common) from [] (warn_slowpath_fmt+0x30/0x40) [ 3.596496] [] (warn_slowpath_fmt) from [] (dss_set_fck_rate+0x6c/0x8c) [ 3.605407] [] (dss_set_fck_rate) from [] (dpi_display_enable+0x23c/0x2e4) [ 3.614562] [] (dpi_display_enable) from [] (sharp_ls_enable+0x58/0xc4) [ 3.623474] [] (sharp_ls_enable) from [] (omapfb_probe+0x548/0x848) [ 3.631988] [] (omapfb_probe) from [] (platform_drv_probe+0x18/0x48) [ 3.640594] [] (platform_drv_probe) from [] (driver_probe_device+0x110/0x22c) [ 3.650024] [] (driver_probe_device) from [] (bus_for_each_drv+0x44/0x8c) [ 3.659088] [] (bus_for_each_drv) from [] (device_attach+0x74/0x8c) [ 3.667541] [] (device_attach) from [] (bus_probe_device+0x88/0xb0) [ 3.676025] [] (bus_probe_device) from [] (deferred_probe_work_func+0x64/0x94) [ 3.685546] [] (deferred_probe_work_func) from [] (process_one_work+0x1b4/0x4bc) [ 3.695251] [] (process_one_work) from [] (worker_thread+0x11c/0x398) [ 3.704620] [] (worker_thread) from [] (kthread+0xc8/0xe4) [ 3.712280] [] (kthread) from [] (ret_from_fork+0x14/0x2c) [ 3.719909] ---[ end trace 1c9526c1a2975498 ]--- > 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, > .parent_clk_name = "dpll4_ck", > .dpi_select_source = &dss_dpi_select_source_omap2_omap3, > }; > -- > 1.8.1.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html