Re: [PATCH] drm/stm: Fix bus_flags handling
On 10/16/20 7:44 PM, Sam Ravnborg wrote: > Hi Marek. Hi, > On Sat, Oct 03, 2020 at 01:07:26AM +0200, Marek Vasut wrote: >> The drm_display_mode_to_videomode() does not populate DISPLAY_FLAGS_DE_LOW >> or DISPLAY_FLAGS_PIXDATA_NEGEDGE flags in struct videomode. > > So after reading this paragrahp I assumed this patch would fix this, alas > there is no changes to drm_modes.c. > Rather than introducing hacks could we try to fix the root cause here? Nope, this is a driver fix, hence the drm/stm tags. > Root cause - as you point out is that there is missing some flags in > the conversion. > Another point is that the stm driver could drop the use of > drm_display_mode_to_videomode() - all the information is available in > drm_display_mode > and using drm_display_mode_to_videomode() does not help much. I kinda already have such a patch in the tree to remove this, but I want to have a patch which fixes the problem described here and can be easily backported to stable too. > If the point is to have easier access to hsync and friendns maybe we > should have a few helpers operating direct on display_mode and not this > conversion to video_mode which is something that belongs to fbdev and > should IMO not be used inside a drm driver. Yep, that is for another patch though, because if that one breaks something, I want to be able to bisect it. ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH] drm/stm: Fix bus_flags handling
Hi Marek.
On Sat, Oct 03, 2020 at 01:07:26AM +0200, Marek Vasut wrote:
> The drm_display_mode_to_videomode() does not populate DISPLAY_FLAGS_DE_LOW
> or DISPLAY_FLAGS_PIXDATA_NEGEDGE flags in struct videomode.
So after reading this paragrahp I assumed this patch would fix this, alas
there is no changes to drm_modes.c.
Rather than introducing hacks could we try to fix the root cause here?
Root cause - as you point out is that there is missing some flags in
the conversion.
Another point is that the stm driver could drop the use of
drm_display_mode_to_videomode() - all the information is available in
drm_display_mode
and using drm_display_mode_to_videomode() does not help much.
If the point is to have easier access to hsync and friendns maybe we
should have a few helpers operating direct on display_mode and not this
conversion to video_mode which is something that belongs to fbdev and
should IMO not be used inside a drm driver.
Sam
> Therefore, no
> matter what polarity the next bridge or display might require, these flags
> are never set, and thus the LTDC GCR_DEPOL and GCR_PCPOL bits are never set,
> and the LTDC behaves as if both DISPLAY_FLAGS_PIXDATA_POSEDGE and
> DISPLAY_FLAGS_DE_HIGH were always set.
>
> The fix for this problem is taken almost verbatim from MXSFB driver. In
> case there is a bridge attached to the LTDC, the bridge might have extra
> polarity requirements, so extract bus_flags from the bridge and use them
> for LTDC configuration. Otherwise, extract bus_flags from the connector,
> which is the display.
>
> Fixes: b759012c5fa7 ("drm/stm: Add STM32 LTDC driver")
> Signed-off-by: Marek Vasut
> Cc: Alexandre Torgue
> Cc: Antonio Borneo
> Cc: Benjamin Gaignard
> Cc: Maxime Coquelin
> Cc: Philippe Cornu
> Cc: Sam Ravnborg
> Cc: Vincent Abriou
> Cc: Yannick Fertre
> Cc: linux-arm-ker...@lists.infradead.org
> Cc: linux-st...@st-md-mailman.stormreply.com
> To: dri-devel@lists.freedesktop.org
> ---
> drivers/gpu/drm/stm/ltdc.c | 22 --
> drivers/gpu/drm/stm/ltdc.h | 2 ++
> 2 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 07c73079293c..a282a1553497 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -546,11 +546,17 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc
> *crtc)
> struct drm_device *ddev = crtc->dev;
> struct drm_display_mode *mode = >state->adjusted_mode;
> struct videomode vm;
> + u32 bus_flags = 0;
> u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
> u32 total_width, total_height;
> u32 val;
> int ret;
>
> + if (ldev->bridge)
> + bus_flags = ldev->bridge->timings->input_bus_flags;
> + else if (ldev->connector)
> + bus_flags = ldev->connector->display_info.bus_flags;
> +
> if (!pm_runtime_active(ddev->dev)) {
> ret = pm_runtime_get_sync(ddev->dev);
> if (ret) {
> @@ -586,10 +592,10 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc
> *crtc)
> if (vm.flags & DISPLAY_FLAGS_VSYNC_HIGH)
> val |= GCR_VSPOL;
>
> - if (vm.flags & DISPLAY_FLAGS_DE_LOW)
> + if (bus_flags & DRM_BUS_FLAG_DE_LOW)
> val |= GCR_DEPOL;
>
> - if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
> + if (bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
> val |= GCR_PCPOL;
>
> reg_update_bits(ldev->regs, LTDC_GCR,
> @@ -1098,6 +1104,8 @@ static const struct drm_encoder_helper_funcs
> ltdc_encoder_helper_funcs = {
>
> static int ltdc_encoder_init(struct drm_device *ddev, struct drm_bridge
> *bridge)
> {
> + struct ltdc_device *ldev = ddev->dev_private;
> + struct drm_connector_list_iter iter;
> struct drm_encoder *encoder;
> int ret;
>
> @@ -1119,6 +1127,16 @@ static int ltdc_encoder_init(struct drm_device *ddev,
> struct drm_bridge *bridge)
> return -EINVAL;
> }
>
> + ldev->bridge = bridge;
> +
> + /*
> + * Get hold of the connector. This is a bit of a hack, until the bridge
> + * API gives us bus flags and formats.
> + */
> + drm_connector_list_iter_begin(ddev, );
> + ldev->connector = drm_connector_list_iter_next();
> + drm_connector_list_iter_end();
> +
> DRM_DEBUG_DRIVER("Bridge encoder:%d created\n", encoder->base.id);
>
> return 0;
> diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
> index f153b908c70e..d0d2c81de29a 100644
> --- a/drivers/gpu/drm/stm/ltdc.h
> +++ b/drivers/gpu/drm/stm/ltdc.h
> @@ -38,6 +38,8 @@ struct ltdc_device {
> u32 irq_status;
> struct fps_info plane_fpsi[LTDC_MAX_LAYER];
> struct drm_atomic_state *suspend_state;
> + struct drm_bridge *bridge;
> + struct drm_connector *connector;
> };
>
> int ltdc_load(struct drm_device *ddev);
> --
> 2.28.0
>
>
[PATCH] drm/stm: Fix bus_flags handling
The drm_display_mode_to_videomode() does not populate DISPLAY_FLAGS_DE_LOW
or DISPLAY_FLAGS_PIXDATA_NEGEDGE flags in struct videomode. Therefore, no
matter what polarity the next bridge or display might require, these flags
are never set, and thus the LTDC GCR_DEPOL and GCR_PCPOL bits are never set,
and the LTDC behaves as if both DISPLAY_FLAGS_PIXDATA_POSEDGE and
DISPLAY_FLAGS_DE_HIGH were always set.
The fix for this problem is taken almost verbatim from MXSFB driver. In
case there is a bridge attached to the LTDC, the bridge might have extra
polarity requirements, so extract bus_flags from the bridge and use them
for LTDC configuration. Otherwise, extract bus_flags from the connector,
which is the display.
Fixes: b759012c5fa7 ("drm/stm: Add STM32 LTDC driver")
Signed-off-by: Marek Vasut
Cc: Alexandre Torgue
Cc: Antonio Borneo
Cc: Benjamin Gaignard
Cc: Maxime Coquelin
Cc: Philippe Cornu
Cc: Sam Ravnborg
Cc: Vincent Abriou
Cc: Yannick Fertre
Cc: linux-arm-ker...@lists.infradead.org
Cc: linux-st...@st-md-mailman.stormreply.com
To: dri-devel@lists.freedesktop.org
---
drivers/gpu/drm/stm/ltdc.c | 22 --
drivers/gpu/drm/stm/ltdc.h | 2 ++
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 07c73079293c..a282a1553497 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -546,11 +546,17 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
struct drm_device *ddev = crtc->dev;
struct drm_display_mode *mode = >state->adjusted_mode;
struct videomode vm;
+ u32 bus_flags = 0;
u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
u32 total_width, total_height;
u32 val;
int ret;
+ if (ldev->bridge)
+ bus_flags = ldev->bridge->timings->input_bus_flags;
+ else if (ldev->connector)
+ bus_flags = ldev->connector->display_info.bus_flags;
+
if (!pm_runtime_active(ddev->dev)) {
ret = pm_runtime_get_sync(ddev->dev);
if (ret) {
@@ -586,10 +592,10 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
if (vm.flags & DISPLAY_FLAGS_VSYNC_HIGH)
val |= GCR_VSPOL;
- if (vm.flags & DISPLAY_FLAGS_DE_LOW)
+ if (bus_flags & DRM_BUS_FLAG_DE_LOW)
val |= GCR_DEPOL;
- if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
+ if (bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
val |= GCR_PCPOL;
reg_update_bits(ldev->regs, LTDC_GCR,
@@ -1098,6 +1104,8 @@ static const struct drm_encoder_helper_funcs
ltdc_encoder_helper_funcs = {
static int ltdc_encoder_init(struct drm_device *ddev, struct drm_bridge
*bridge)
{
+ struct ltdc_device *ldev = ddev->dev_private;
+ struct drm_connector_list_iter iter;
struct drm_encoder *encoder;
int ret;
@@ -1119,6 +1127,16 @@ static int ltdc_encoder_init(struct drm_device *ddev,
struct drm_bridge *bridge)
return -EINVAL;
}
+ ldev->bridge = bridge;
+
+ /*
+* Get hold of the connector. This is a bit of a hack, until the bridge
+* API gives us bus flags and formats.
+*/
+ drm_connector_list_iter_begin(ddev, );
+ ldev->connector = drm_connector_list_iter_next();
+ drm_connector_list_iter_end();
+
DRM_DEBUG_DRIVER("Bridge encoder:%d created\n", encoder->base.id);
return 0;
diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
index f153b908c70e..d0d2c81de29a 100644
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -38,6 +38,8 @@ struct ltdc_device {
u32 irq_status;
struct fps_info plane_fpsi[LTDC_MAX_LAYER];
struct drm_atomic_state *suspend_state;
+ struct drm_bridge *bridge;
+ struct drm_connector *connector;
};
int ltdc_load(struct drm_device *ddev);
--
2.28.0
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