Re: [Intel-gfx] [PATCH v3 4/7] drm/fb-helper: Apply panel orientation connector prop to the primary

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 30-10-17 10:52, Daniel Vetter wrote:
> On Mon, Oct 23, 2017 at 09:14:22AM +0200, Hans de Goede wrote:
>> Apply the "panel orientation" drm connector prop to the primary plane so
>> that fbcon and fbdev using userspace programs display the right way up.
>>
>> Fixes: https://bugs.freedesktop.org/show_bug.cgi?id”894
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>> Changes in v2:
>> -New patch in v2 of this patch-set
>>
>> Changes in v3:
>> -Use a rotation member in struct drm_fb_helper_crtc and set that from
>>   drm_setup_crtcs instead of looping over all crtc's to find the right one
>>   later
>> -Since we now no longer look at rotation quirks directly in the fbcon code,
>>   set fb_info.fbcon_rotate_hint when the panel is not mounted upright and
>>   we cannot use hardware rotation
>> ---
>>   drivers/gpu/drm/drm_fb_helper.c | 76 +++++++++++++++++++++++++++++++++++++++--
>>   include/drm/drm_fb_helper.h     |  8 +++++
>>   2 files changed, 82 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
>> index 116d1f1337c7..e0f95f2cc52f 100644
>> --- a/drivers/gpu/drm/drm_fb_helper.c
>> +++ b/drivers/gpu/drm/drm_fb_helper.c
>> @@ -41,6 +41,7 @@
>>   #include <drm/drm_atomic.h>
>>   #include <drm/drm_atomic_helper.h>
>>   
>> +#include "drm_crtc_internal.h"
>>   #include "drm_crtc_helper_internal.h"
>>   
>>   static bool drm_fbdev_emulation = true;
>> @@ -350,6 +351,7 @@ EXPORT_SYMBOL(drm_fb_helper_debug_leave);
>>   static int restore_fbdev_mode_atomic(struct drm_fb_helper *fb_helper, bool active)
>>   {
>>   	struct drm_device *dev = fb_helper->dev;
>> +	struct drm_plane_state *plane_state;
>>   	struct drm_plane *plane;
>>   	struct drm_atomic_state *state;
>>   	int i, ret;
>> @@ -368,8 +370,6 @@ static int restore_fbdev_mode_atomic(struct drm_fb_helper *fb_helper, bool activ
>>   retry:
>>   	plane_mask = 0;
>>   	drm_for_each_plane(plane, dev) {
>> -		struct drm_plane_state *plane_state;
>> -
>>   		plane_state = drm_atomic_get_plane_state(state, plane);
>>   		if (IS_ERR(plane_state)) {
>>   			ret = PTR_ERR(plane_state);
>> @@ -392,6 +392,11 @@ static int restore_fbdev_mode_atomic(struct drm_fb_helper *fb_helper, bool activ
>>   
>>   	for (i = 0; i < fb_helper->crtc_count; i++) {
>>   		struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
>> +		struct drm_plane *primary = mode_set->crtc->primary;
>> +
>> +		/* Cannot fail as we've already gotten the plane state above */
>> +		plane_state = drm_atomic_get_new_plane_state(state, primary);
>> +		plane_state->rotation = fb_helper->crtc_info[i].rotation;
>>   
>>   		ret = __drm_atomic_helper_set_config(mode_set, state);
>>   		if (ret != 0)
>> @@ -2334,6 +2339,57 @@ static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
>>   	return best_score;
>>   }
>>   
>> +/*
>> + * This function checks if rotation is necessary because of panel orientation
>> + * and if it is, if it is supported.
>> + * If rotation is necessary and supported, its gets set in fb_crtc.rotation.
>> + * If rotation is necessary but not supported, a DRM_MODE_ROTATE_* flag gets
>> + * or-ed into fb_helper->rotations. In drm_setup_crtcs_fb() we check if only
>> + * one bit is set and then we set fb_info.fbcon_rotate_hint to make fbcon do
>> + * the unsupported rotation.
>> + */
>> +static void drm_setup_crtc_rotation(struct drm_fb_helper *fb_helper,
>> +				    struct drm_fb_helper_crtc *fb_crtc,
>> +				    struct drm_connector *connector)
>> +{
>> +	struct drm_plane *plane = fb_crtc->mode_set.crtc->primary;
>> +	uint64_t valid_mask = 0;
>> +	int i, rotation;
>> +
>> +	fb_crtc->rotation = DRM_MODE_ROTATE_0;
>> +
>> +	switch (connector->display_info.panel_orientation) {
>> +	case DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP:
>> +		rotation = DRM_MODE_ROTATE_180;
>> +		break;
>> +	case DRM_MODE_PANEL_ORIENTATION_LEFT_UP:
>> +		rotation = DRM_MODE_ROTATE_90;
>> +		break;
>> +	case DRM_MODE_PANEL_ORIENTATION_RIGHT_UP:
>> +		rotation = DRM_MODE_ROTATE_270;
>> +		break;
> 
> For 90/270 hw rotation you need to flip the coordinates/sizes of the fb.

You're probably right, I don't have any hardware supporting
270 degree rotation to test this with.

>> +	default:
>> +		rotation = DRM_MODE_ROTATE_0;
>> +	}
>> +
>> +	if (rotation = DRM_MODE_ROTATE_0 || !plane->rotation_property) {
>> +		fb_helper->rotations |= rotation;
>> +		return;
>> +	}
>> +
>> +	for (i = 0; i < plane->rotation_property->num_values; i++)
>> +		valid_mask |= (1ULL << plane->rotation_property->values[i]);
> 
> This isn't a good enough check for atomic drivers (and not for gen9+ intel
> hw), since we might expose 90° rotations, but it only works if you have
> the correct tiling format.
> 
> For atomic drivers it'd be really good if we could do a TEST_ONLY commit
> first, and if that fails, fall back to sw rotation.
> 
> But that poses a bit a chicken&egg with creating the framebuffer (we need
> one for the TEST_ONLY), so probably a bit too much more for this. And
> afaiui your quirk list only applies to older stuff.
> 
> At least add a FIXME meanwhile? In a way we have a FIXME already for
> multi-pipe, since we don't try to fall back to fewer pipes if the single
> atomic commit failed.
> 
> Or maybe just don't use 90/270 hw rotation for now since it seems buggy in
> your code anyway.

I was wondering about this (need for special fb layout) myself too, I
agree also given the above comment that it is probably best to only
support 0/180 degree hardware rotation for now, I will do for the next
version (and add a TODO comment).


>> +
>> +	if (!(rotation & valid_mask)) {
>> +		fb_helper->rotations |= rotation;
>> +		return;
>> +	}
>> +
>> +	fb_crtc->rotation = rotation;
>> +	/* Rotating in hardware, fbcon should not rotate */
>> +	fb_helper->rotations |= DRM_MODE_ROTATE_0;
> 
> Wrong bitopt I think.

No this is intentional, if we've a panel requiring say 90 degree rotation
which we will do in software and another panel (weird example) doing 180
degree rotation in hardware, then we want to or both
DRM_MODE_ROTATE_90 and DRM_MODE_ROTATE_0 into the rotations bitmask
(0 since the hardware rotation requires no sw rotation).
The rotations bitmask is the *combination* of all rotations we need
fbcon to do in software and when that ends up being more then one
rotation we chicken out and just don't do any software rotation,
maybe I should rename rotations to sw_rotations?

A better real world example is a 90 degree rotated panel with
an external monitor, in that case for the panel we hit:

	if (!(rotation & valid_mask)) {
		fb_helper->rotations |= rotation;
		return;
	}

Or-ing in the panel's DRM_MODE_ROTATE_90.

And for the monitor we hit:

	if (rotation = DRM_MODE_ROTATE_0 || !plane->rotation_property) {
		fb_helper->rotations |= rotation;
		return;
	}

Or-ing in the monitors's DRM_MODE_ROTATE_0.

So we end up with 2 bits set in fb_helper->rotations, hitting the
default in the switch case and picking FB_ROTATE_UR, since we cannot
satisfy both rotations in fbcon at the same time.


> Or you're doing some really funny control logic by oring in another value
> to hit the default case below which doesn't rotate anything. I think that
> should be done explicitly, by explicitly setting to rotation to ROTATE_0
> instead of this. Same for the check above.

I hope my explanation above explains why I'm or-ing together rotations,
basically I want to detect if we need more then 1 type of software-rotation
in fbcon and in that case bail out and fallback to FB_ROTATE_UR.

Regards,

Hans


> 
>> +}
>> +
>>   static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
>>   			    u32 width, u32 height)
>>   {
>> @@ -2393,6 +2449,7 @@ static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
>>   		drm_fb_helper_modeset_release(fb_helper,
>>   					      &fb_helper->crtc_info[i].mode_set);
>>   
>> +	fb_helper->rotations = 0;
>>   	drm_fb_helper_for_each_connector(fb_helper, i) {
>>   		struct drm_display_mode *mode = modes[i];
>>   		struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
>> @@ -2412,6 +2469,7 @@ static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
>>   			modeset->mode = drm_mode_duplicate(dev,
>>   							   fb_crtc->desired_mode);
>>   			drm_connector_get(connector);
>> +			drm_setup_crtc_rotation(fb_helper, fb_crtc, connector);
>>   			modeset->connectors[modeset->num_connectors++] = connector;
>>   			modeset->x = offset->x;
>>   			modeset->y = offset->y;
>> @@ -2453,6 +2511,20 @@ static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
>>   		}
>>   	}
>>   	mutex_unlock(&fb_helper->dev->mode_config.mutex);
>> +
>> +	switch (fb_helper->rotations) {
>> +	case DRM_MODE_ROTATE_90:
>> +		info->fbcon_rotate_hint = FB_ROTATE_CCW;
>> +		break;
>> +	case DRM_MODE_ROTATE_180:
>> +		info->fbcon_rotate_hint = FB_ROTATE_UD;
>> +		break;
>> +	case DRM_MODE_ROTATE_270:
>> +		info->fbcon_rotate_hint = FB_ROTATE_CW;
>> +		break;
>> +	default:
>> +		info->fbcon_rotate_hint = FB_ROTATE_UR;
>> +	}
>>   }
>>   
>>   /* Note: Drops fb_helper->lock before returning. */
>> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
>> index 33fe95927742..4ee834a077a2 100644
>> --- a/include/drm/drm_fb_helper.h
>> +++ b/include/drm/drm_fb_helper.h
>> @@ -48,6 +48,7 @@ struct drm_fb_helper_crtc {
>>   	struct drm_mode_set mode_set;
>>   	struct drm_display_mode *desired_mode;
>>   	int x, y;
>> +	int rotation;
>>   };
>>   
>>   /**
>> @@ -158,6 +159,13 @@ struct drm_fb_helper {
>>   	struct drm_fb_helper_crtc *crtc_info;
>>   	int connector_count;
>>   	int connector_info_alloc_count;
>> +	/**
>> +	 * @rotations:
>> +	 * Bitmask of all rotations requested for panel-orientation which
>> +	 * could not be handled in hardware. If only one bit is set
>> +	 * fbdev->fbcon_rotate_hint gets set to the requested rotation.
>> +	 */
>> +	int rotations;
>>   	/**
>>   	 * @connector_info:
>>   	 *
>> -- 
>> 2.14.2
>>
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