[0/2] drm/sun4i: Fix sun8i HDMI PHY initialization

Message

Jernej Škrabec May 14, 2019, 8:43 p.m. UTC

I received a report that 4K resolution doesn't work if U-Boot video
driver is disabled. It turns out that HDMI PHY clock driver was
initialized prematurely, before reset line was deasserted and clocks
enabled. U-Boot video driver masked the issue because it set pixel
clock correctly.

In the process of researching the bug, I also found out that few bits
in HDMI PHY registers were not set correctly. While there is no
noticeable change (4K resolution works with both settings), I've
added fix anyway, to be conformant with vendor documentation.

Please check it out.

Best regards,
Jernej

Jernej Skrabec (2):
  drm/sun4i: Fix sun8i HDMI PHY clock initialization
  drm/sun4i: Fix sun8i HDMI PHY configuration for > 148.5 MHz

 drivers/gpu/drm/sun4i/sun8i_hdmi_phy.c | 29 ++++++++++++++------------
 1 file changed, 16 insertions(+), 13 deletions(-)

Comments

Maxime Ripard May 16, 2019, 8:31 a.m. UTC | #1

On Tue, May 14, 2019 at 10:43:35PM +0200, Jernej Skrabec wrote:
> I received a report that 4K resolution doesn't work if U-Boot video
> driver is disabled. It turns out that HDMI PHY clock driver was
> initialized prematurely, before reset line was deasserted and clocks
> enabled. U-Boot video driver masked the issue because it set pixel
> clock correctly.
>
> In the process of researching the bug, I also found out that few bits
> in HDMI PHY registers were not set correctly. While there is no
> noticeable change (4K resolution works with both settings), I've
> added fix anyway, to be conformant with vendor documentation.

Applied both, thanks

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com