On 19/01/16 15:10, Fabio Estevam wrote: > From: Fabio Estevam <fabio.estevam@xxxxxxx> > > Currently when we boot the kernel on a mx25pdk the LCDC controller > does not show the Linux logo on boot. > > This problem is well explained by Sascha Hauer: > > "Unfortunately this LCD controller does not have an enable bit. The > controller starts directly when the clocks are enabled. If the clocks > are enabled when the controller is not yet programmed with proper > register values then it just goes into some undefined state. What I > suspect is that the clocks already were enabled before driver probe, > presumably by the bootloader, so the controller is already in undefined > state when entering Linux. Now by dis/enabling the ipg clock you > effectively reset the controller. Since you have programmed it with > valid register values in the mean time it starts working after this > reset." > > So do as suggested and force a reset of the LCDC hardware by > enabling and disabling the IPG clock. > > With this change the Linux logo can be seen on boot on a mx25pdk. > > Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx> > --- > drivers/video/fbdev/imxfb.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) Thanks. Queued for 4.5 fixes. Tomi
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