From: Adam Ford aford173@gmail.com
There appears to be a timing issue where using a divider of 32 breaks the DSS for OMAP36xx despite the TRM stating 32 is a valid number. Through experimentation, it appears that 31 works.
This same fix was issued for kernels 4.5+. However, between kernels 4.4 and 4.5, the directory structure was changed when the dss directory was moved inside the omapfb directory. That broke the patch on kernels older than 4.5, because it didn't permit the patch to apply cleanly for 4.4 and older.
A similar patch was applied to the 3.16 kernel already, but not to 4.4. Commit 4b911101a5cd ("drm/omap: fix max fclk divider for omap36xx") is on the 3.16 stable branch with notes from Ben about the path change.
Since this was applied for 3.16 already, this patch is for kernels 3.17 through 4.4 only.
Fixes: f7018c213502 ("video: move fbdev to drivers/video/fbdev") Cc: stable@vger.kernel.org #3.17 - 4.4 CC: tomi.valkeinen@ti.com Signed-off-by: Adam Ford aford173@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/video/fbdev/omap2/dss/dss.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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 omap34x };
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,