| Message ID | 20210204184710.1880895-3-jernej.skrabec@siol.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | sunxi: fix H6 HDMI related issues | expand |
On Fri, Feb 5, 2021 at 2:48 AM Jernej Skrabec <jernej.skrabec@siol.net> wrote: > > Channel 1 has polarity bits for vsync and hsync signals but driver never > sets them. It turns out that with pre-HDMI2 controllers seemingly there > is no issue if polarity is not set. However, with HDMI2 controllers > (H6) there often comes to de-synchronization due to phase shift. This > causes flickering screen. It's safe to assume that similar issues might > happen also with pre-HDMI2 controllers. > > Solve issue with setting vsync and hsync polarity. Note that display > stacks with tcon top have polarity bits actually in tcon0 polarity > register. > > Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support") > Tested-by: Andre Heider <a.heider@gmail.com> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> > --- > drivers/gpu/drm/sun4i/sun4i_tcon.c | 24 ++++++++++++++++++++++++ > drivers/gpu/drm/sun4i/sun4i_tcon.h | 5 +++++ > 2 files changed, 29 insertions(+) > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c > index 6b9af4c08cd6..0d132dae58c0 100644 > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > @@ -672,6 +672,29 @@ static void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon, > SUN4I_TCON1_BASIC5_V_SYNC(vsync) | > SUN4I_TCON1_BASIC5_H_SYNC(hsync)); > > + /* Setup the polarity of sync signals */ > + if (tcon->quirks->polarity_in_ch0) { > + val = 0; > + > + if (mode->flags & DRM_MODE_FLAG_PHSYNC) > + val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE; > + > + if (mode->flags & DRM_MODE_FLAG_PVSYNC) > + val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; > + > + regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val); > + } else { > + val = SUN4I_TCON1_IO_POL_UNKNOWN; I think a comment for the origin of this is warranted. Otherwise, Reviewed-by: Chen-Yu Tsai <wens@csie.org> > + > + if (mode->flags & DRM_MODE_FLAG_PHSYNC) > + val |= SUN4I_TCON1_IO_POL_HSYNC_POSITIVE; > + > + if (mode->flags & DRM_MODE_FLAG_PVSYNC) > + val |= SUN4I_TCON1_IO_POL_VSYNC_POSITIVE; > + > + regmap_write(tcon->regs, SUN4I_TCON1_IO_POL_REG, val); > + } > + > /* Map output pins to channel 1 */ > regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG, > SUN4I_TCON_GCTL_IOMAP_MASK, > @@ -1500,6 +1523,7 @@ static const struct sun4i_tcon_quirks sun8i_a83t_tv_quirks = { > > static const struct sun4i_tcon_quirks sun8i_r40_tv_quirks = { > .has_channel_1 = true, > + .polarity_in_ch0 = true, > .set_mux = sun8i_r40_tcon_tv_set_mux, > }; > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h > index c5ac1b02482c..b504fb2d3de5 100644 > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.h > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h > @@ -154,6 +154,10 @@ > #define SUN4I_TCON1_BASIC5_V_SYNC(height) (((height) - 1) & 0x3ff) > > #define SUN4I_TCON1_IO_POL_REG 0xf0 > +#define SUN4I_TCON1_IO_POL_UNKNOWN BIT(26) > +#define SUN4I_TCON1_IO_POL_HSYNC_POSITIVE BIT(25) > +#define SUN4I_TCON1_IO_POL_VSYNC_POSITIVE BIT(24) > + > #define SUN4I_TCON1_IO_TRI_REG 0xf4 > > #define SUN4I_TCON_ECC_FIFO_REG 0xf8 > @@ -236,6 +240,7 @@ struct sun4i_tcon_quirks { > bool needs_de_be_mux; /* sun6i needs mux to select backend */ > bool needs_edp_reset; /* a80 edp reset needed for tcon0 access */ > bool supports_lvds; /* Does the TCON support an LVDS output? */ > + bool polarity_in_ch0; /* some tcon1 channels have polarity bits in tcon0 pol register */ > u8 dclk_min_div; /* minimum divider for TCON0 DCLK */ > > /* callback to handle tcon muxing options */ > -- > 2.30.0 >
On Fri, Feb 05, 2021 at 11:21:22AM +0800, Chen-Yu Tsai wrote: > On Fri, Feb 5, 2021 at 2:48 AM Jernej Skrabec <jernej.skrabec@siol.net> wrote: > > > > Channel 1 has polarity bits for vsync and hsync signals but driver never > > sets them. It turns out that with pre-HDMI2 controllers seemingly there > > is no issue if polarity is not set. However, with HDMI2 controllers > > (H6) there often comes to de-synchronization due to phase shift. This > > causes flickering screen. It's safe to assume that similar issues might > > happen also with pre-HDMI2 controllers. > > > > Solve issue with setting vsync and hsync polarity. Note that display > > stacks with tcon top have polarity bits actually in tcon0 polarity > > register. > > > > Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support") > > Tested-by: Andre Heider <a.heider@gmail.com> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> > > --- > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 24 ++++++++++++++++++++++++ > > drivers/gpu/drm/sun4i/sun4i_tcon.h | 5 +++++ > > 2 files changed, 29 insertions(+) > > > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > index 6b9af4c08cd6..0d132dae58c0 100644 > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > @@ -672,6 +672,29 @@ static void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon, > > SUN4I_TCON1_BASIC5_V_SYNC(vsync) | > > SUN4I_TCON1_BASIC5_H_SYNC(hsync)); > > > > + /* Setup the polarity of sync signals */ > > + if (tcon->quirks->polarity_in_ch0) { > > + val = 0; > > + > > + if (mode->flags & DRM_MODE_FLAG_PHSYNC) > > + val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE; > > + > > + if (mode->flags & DRM_MODE_FLAG_PVSYNC) > > + val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; > > + > > + regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val); > > + } else { > > + val = SUN4I_TCON1_IO_POL_UNKNOWN; > > I think a comment for the origin of this is warranted. If it's anything like TCON0, it's the pixel clock polarity Maxime
Dne petek, 05. februar 2021 ob 17:01:30 CET je Maxime Ripard napisal(a): > On Fri, Feb 05, 2021 at 11:21:22AM +0800, Chen-Yu Tsai wrote: > > On Fri, Feb 5, 2021 at 2:48 AM Jernej Skrabec <jernej.skrabec@siol.net> wrote: > > > > > > Channel 1 has polarity bits for vsync and hsync signals but driver never > > > sets them. It turns out that with pre-HDMI2 controllers seemingly there > > > is no issue if polarity is not set. However, with HDMI2 controllers > > > (H6) there often comes to de-synchronization due to phase shift. This > > > causes flickering screen. It's safe to assume that similar issues might > > > happen also with pre-HDMI2 controllers. > > > > > > Solve issue with setting vsync and hsync polarity. Note that display > > > stacks with tcon top have polarity bits actually in tcon0 polarity > > > register. > > > > > > Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support") > > > Tested-by: Andre Heider <a.heider@gmail.com> > > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> > > > --- > > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 24 ++++++++++++++++++++++++ > > > drivers/gpu/drm/sun4i/sun4i_tcon.h | 5 +++++ > > > 2 files changed, 29 insertions(+) > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/ sun4i_tcon.c > > > index 6b9af4c08cd6..0d132dae58c0 100644 > > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > @@ -672,6 +672,29 @@ static void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon, > > > SUN4I_TCON1_BASIC5_V_SYNC(vsync) | > > > SUN4I_TCON1_BASIC5_H_SYNC(hsync)); > > > > > > + /* Setup the polarity of sync signals */ > > > + if (tcon->quirks->polarity_in_ch0) { > > > + val = 0; > > > + > > > + if (mode->flags & DRM_MODE_FLAG_PHSYNC) > > > + val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE; > > > + > > > + if (mode->flags & DRM_MODE_FLAG_PVSYNC) > > > + val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; > > > + > > > + regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val); > > > + } else { > > > + val = SUN4I_TCON1_IO_POL_UNKNOWN; > > > > I think a comment for the origin of this is warranted. > > If it's anything like TCON0, it's the pixel clock polarity Hard to say, DW HDMI controller has "data enable" polarity along hsync and vsync. It could be either or none of those. What should I write in comment? BSP drivers and documentation use only generic names like io2_inv. Best regards, Jernej
On Sat, Feb 6, 2021 at 12:21 AM Jernej Škrabec <jernej.skrabec@siol.net> wrote: > > Dne petek, 05. februar 2021 ob 17:01:30 CET je Maxime Ripard napisal(a): > > On Fri, Feb 05, 2021 at 11:21:22AM +0800, Chen-Yu Tsai wrote: > > > On Fri, Feb 5, 2021 at 2:48 AM Jernej Skrabec <jernej.skrabec@siol.net> > wrote: > > > > > > > > Channel 1 has polarity bits for vsync and hsync signals but driver never > > > > sets them. It turns out that with pre-HDMI2 controllers seemingly there > > > > is no issue if polarity is not set. However, with HDMI2 controllers > > > > (H6) there often comes to de-synchronization due to phase shift. This > > > > causes flickering screen. It's safe to assume that similar issues might > > > > happen also with pre-HDMI2 controllers. > > > > > > > > Solve issue with setting vsync and hsync polarity. Note that display > > > > stacks with tcon top have polarity bits actually in tcon0 polarity > > > > register. > > > > > > > > Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support") > > > > Tested-by: Andre Heider <a.heider@gmail.com> > > > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> > > > > --- > > > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 24 ++++++++++++++++++++++++ > > > > drivers/gpu/drm/sun4i/sun4i_tcon.h | 5 +++++ > > > > 2 files changed, 29 insertions(+) > > > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/ > sun4i_tcon.c > > > > index 6b9af4c08cd6..0d132dae58c0 100644 > > > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > @@ -672,6 +672,29 @@ static void sun4i_tcon1_mode_set(struct sun4i_tcon > *tcon, > > > > SUN4I_TCON1_BASIC5_V_SYNC(vsync) | > > > > SUN4I_TCON1_BASIC5_H_SYNC(hsync)); > > > > > > > > + /* Setup the polarity of sync signals */ > > > > + if (tcon->quirks->polarity_in_ch0) { > > > > + val = 0; > > > > + > > > > + if (mode->flags & DRM_MODE_FLAG_PHSYNC) > > > > + val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE; > > > > + > > > > + if (mode->flags & DRM_MODE_FLAG_PVSYNC) > > > > + val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; > > > > + > > > > + regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val); > > > > + } else { > > > > + val = SUN4I_TCON1_IO_POL_UNKNOWN; > > > > > > I think a comment for the origin of this is warranted. > > > > If it's anything like TCON0, it's the pixel clock polarity > > Hard to say, DW HDMI controller has "data enable" polarity along hsync and > vsync. It could be either or none of those. > > What should I write in comment? BSP drivers and documentation use only generic > names like io2_inv. Just say that we don't know exactly what it is, but it is required for things to work properly? Would be interesting to know what happens if you don't set this bit, but do set VSYNC/HSYNC polarity properly. ChenYu
Dne petek, 05. februar 2021 ob 17:28:23 CET je Chen-Yu Tsai napisal(a): > On Sat, Feb 6, 2021 at 12:21 AM Jernej Škrabec <jernej.skrabec@siol.net> wrote: > > > > Dne petek, 05. februar 2021 ob 17:01:30 CET je Maxime Ripard napisal(a): > > > On Fri, Feb 05, 2021 at 11:21:22AM +0800, Chen-Yu Tsai wrote: > > > > On Fri, Feb 5, 2021 at 2:48 AM Jernej Skrabec <jernej.skrabec@siol.net> > > wrote: > > > > > > > > > > Channel 1 has polarity bits for vsync and hsync signals but driver never > > > > > sets them. It turns out that with pre-HDMI2 controllers seemingly there > > > > > is no issue if polarity is not set. However, with HDMI2 controllers > > > > > (H6) there often comes to de-synchronization due to phase shift. This > > > > > causes flickering screen. It's safe to assume that similar issues might > > > > > happen also with pre-HDMI2 controllers. > > > > > > > > > > Solve issue with setting vsync and hsync polarity. Note that display > > > > > stacks with tcon top have polarity bits actually in tcon0 polarity > > > > > register. > > > > > > > > > > Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support") > > > > > Tested-by: Andre Heider <a.heider@gmail.com> > > > > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> > > > > > --- > > > > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 24 ++++++++++++++++++++++++ > > > > > drivers/gpu/drm/sun4i/sun4i_tcon.h | 5 +++++ > > > > > 2 files changed, 29 insertions(+) > > > > > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/ sun4i/ > > sun4i_tcon.c > > > > > index 6b9af4c08cd6..0d132dae58c0 100644 > > > > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > > @@ -672,6 +672,29 @@ static void sun4i_tcon1_mode_set(struct sun4i_tcon > > *tcon, > > > > > SUN4I_TCON1_BASIC5_V_SYNC(vsync) | > > > > > SUN4I_TCON1_BASIC5_H_SYNC(hsync)); > > > > > > > > > > + /* Setup the polarity of sync signals */ > > > > > + if (tcon->quirks->polarity_in_ch0) { > > > > > + val = 0; > > > > > + > > > > > + if (mode->flags & DRM_MODE_FLAG_PHSYNC) > > > > > + val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE; > > > > > + > > > > > + if (mode->flags & DRM_MODE_FLAG_PVSYNC) > > > > > + val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; > > > > > + > > > > > + regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val); > > > > > + } else { > > > > > + val = SUN4I_TCON1_IO_POL_UNKNOWN; > > > > > > > > I think a comment for the origin of this is warranted. > > > > > > If it's anything like TCON0, it's the pixel clock polarity > > > > Hard to say, DW HDMI controller has "data enable" polarity along hsync and > > vsync. It could be either or none of those. > > > > What should I write in comment? BSP drivers and documentation use only generic > > names like io2_inv. > > Just say that we don't know exactly what it is, but it is required for things > to work properly? Would be interesting to know what happens if you don't set > this bit, but do set VSYNC/HSYNC polarity properly. Nothing seems to happen - tested on H3 with HDMI (4k@30) and CVBS. At least I didn't notice anything. Best regards, Jernej
On Fri, Feb 05, 2021 at 07:47:17PM +0100, Jernej Škrabec wrote: > Dne petek, 05. februar 2021 ob 17:28:23 CET je Chen-Yu Tsai napisal(a): > > On Sat, Feb 6, 2021 at 12:21 AM Jernej Škrabec <jernej.skrabec@siol.net> > wrote: > > > > > > Dne petek, 05. februar 2021 ob 17:01:30 CET je Maxime Ripard napisal(a): > > > > On Fri, Feb 05, 2021 at 11:21:22AM +0800, Chen-Yu Tsai wrote: > > > > > On Fri, Feb 5, 2021 at 2:48 AM Jernej Skrabec > <jernej.skrabec@siol.net> > > > wrote: > > > > > > > > > > > > Channel 1 has polarity bits for vsync and hsync signals but driver > never > > > > > > sets them. It turns out that with pre-HDMI2 controllers seemingly > there > > > > > > is no issue if polarity is not set. However, with HDMI2 controllers > > > > > > (H6) there often comes to de-synchronization due to phase shift. > This > > > > > > causes flickering screen. It's safe to assume that similar issues > might > > > > > > happen also with pre-HDMI2 controllers. > > > > > > > > > > > > Solve issue with setting vsync and hsync polarity. Note that display > > > > > > stacks with tcon top have polarity bits actually in tcon0 polarity > > > > > > register. > > > > > > > > > > > > Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine > support") > > > > > > Tested-by: Andre Heider <a.heider@gmail.com> > > > > > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> > > > > > > --- > > > > > > drivers/gpu/drm/sun4i/sun4i_tcon.c | 24 ++++++++++++++++++++++++ > > > > > > drivers/gpu/drm/sun4i/sun4i_tcon.h | 5 +++++ > > > > > > 2 files changed, 29 insertions(+) > > > > > > > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/ > sun4i/ > > > sun4i_tcon.c > > > > > > index 6b9af4c08cd6..0d132dae58c0 100644 > > > > > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c > > > > > > @@ -672,6 +672,29 @@ static void sun4i_tcon1_mode_set(struct > sun4i_tcon > > > *tcon, > > > > > > SUN4I_TCON1_BASIC5_V_SYNC(vsync) | > > > > > > SUN4I_TCON1_BASIC5_H_SYNC(hsync)); > > > > > > > > > > > > + /* Setup the polarity of sync signals */ > > > > > > + if (tcon->quirks->polarity_in_ch0) { > > > > > > + val = 0; > > > > > > + > > > > > > + if (mode->flags & DRM_MODE_FLAG_PHSYNC) > > > > > > + val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE; > > > > > > + > > > > > > + if (mode->flags & DRM_MODE_FLAG_PVSYNC) > > > > > > + val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; > > > > > > + > > > > > > + regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, > val); > > > > > > + } else { > > > > > > + val = SUN4I_TCON1_IO_POL_UNKNOWN; > > > > > > > > > > I think a comment for the origin of this is warranted. > > > > > > > > If it's anything like TCON0, it's the pixel clock polarity > > > > > > Hard to say, DW HDMI controller has "data enable" polarity along hsync and > > > vsync. It could be either or none of those. > > > > > > What should I write in comment? BSP drivers and documentation use only > generic > > > names like io2_inv. > > > > Just say that we don't know exactly what it is, but it is required for > things > > to work properly? Would be interesting to know what happens if you don't set > > this bit, but do set VSYNC/HSYNC polarity properly. > > Nothing seems to happen - tested on H3 with HDMI (4k@30) and CVBS. At least I > didn't notice anything. That's pretty normal, an inverted pixel clock would at worst give you some weird artifacts and / or pixels being of the wrong color. Data enable on the other hand would very likely stall the HDMI controller since you would have only the blanking periods that would be considered valid. Maxime
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 6b9af4c08cd6..0d132dae58c0 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -672,6 +672,29 @@ static void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon, SUN4I_TCON1_BASIC5_V_SYNC(vsync) | SUN4I_TCON1_BASIC5_H_SYNC(hsync)); + /* Setup the polarity of sync signals */ + if (tcon->quirks->polarity_in_ch0) { + val = 0; + + if (mode->flags & DRM_MODE_FLAG_PHSYNC) + val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE; + + if (mode->flags & DRM_MODE_FLAG_PVSYNC) + val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE; + + regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val); + } else { + val = SUN4I_TCON1_IO_POL_UNKNOWN; + + if (mode->flags & DRM_MODE_FLAG_PHSYNC) + val |= SUN4I_TCON1_IO_POL_HSYNC_POSITIVE; + + if (mode->flags & DRM_MODE_FLAG_PVSYNC) + val |= SUN4I_TCON1_IO_POL_VSYNC_POSITIVE; + + regmap_write(tcon->regs, SUN4I_TCON1_IO_POL_REG, val); + } + /* Map output pins to channel 1 */ regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG, SUN4I_TCON_GCTL_IOMAP_MASK, @@ -1500,6 +1523,7 @@ static const struct sun4i_tcon_quirks sun8i_a83t_tv_quirks = { static const struct sun4i_tcon_quirks sun8i_r40_tv_quirks = { .has_channel_1 = true, + .polarity_in_ch0 = true, .set_mux = sun8i_r40_tcon_tv_set_mux, }; diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h index c5ac1b02482c..b504fb2d3de5 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.h +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h @@ -154,6 +154,10 @@ #define SUN4I_TCON1_BASIC5_V_SYNC(height) (((height) - 1) & 0x3ff) #define SUN4I_TCON1_IO_POL_REG 0xf0 +#define SUN4I_TCON1_IO_POL_UNKNOWN BIT(26) +#define SUN4I_TCON1_IO_POL_HSYNC_POSITIVE BIT(25) +#define SUN4I_TCON1_IO_POL_VSYNC_POSITIVE BIT(24) + #define SUN4I_TCON1_IO_TRI_REG 0xf4 #define SUN4I_TCON_ECC_FIFO_REG 0xf8 @@ -236,6 +240,7 @@ struct sun4i_tcon_quirks { bool needs_de_be_mux; /* sun6i needs mux to select backend */ bool needs_edp_reset; /* a80 edp reset needed for tcon0 access */ bool supports_lvds; /* Does the TCON support an LVDS output? */ + bool polarity_in_ch0; /* some tcon1 channels have polarity bits in tcon0 pol register */ u8 dclk_min_div; /* minimum divider for TCON0 DCLK */ /* callback to handle tcon muxing options */
Channel 1 has polarity bits for vsync and hsync signals but driver never sets them. It turns out that with pre-HDMI2 controllers seemingly there is no issue if polarity is not set. However, with HDMI2 controllers (H6) there often comes to de-synchronization due to phase shift. This causes flickering screen. It's safe to assume that similar issues might happen also with pre-HDMI2 controllers. Solve issue with setting vsync and hsync polarity. Note that display stacks with tcon top have polarity bits actually in tcon0 polarity register. Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support") Tested-by: Andre Heider <a.heider@gmail.com> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 24 ++++++++++++++++++++++++ drivers/gpu/drm/sun4i/sun4i_tcon.h | 5 +++++ 2 files changed, 29 insertions(+)