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

Hans de Goede hdegoede at redhat.com
Tue Oct 31 10:24:14 UTC 2017


Hi,

On 31-10-17 11:14, Daniel Vetter wrote:
> On Mon, Oct 30, 2017 at 12:09:27PM +0100, Hans de Goede wrote:
>> 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=94894
>>>> Signed-off-by: Hans de Goede <hdegoede at 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).
> 
> It'll work on i915 at least, on current hw. Might still be broken on
> other, but then that's a larger issue with the fbcon atomic code right
> now.
>>
>>
>>>> +
>>>> +	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.
> 
> Yeah I suspected this is what you're trying to do, but imo it's too clear.
> Can't we do an explicit check for this instead of uncommented magic

Erm, my patch contains a big(ish) comment above drm_setup_crtc_rotation which
tries to explain this already.
> that takes half an hour to understand? I'm thinking of
> 
> if (count_bits(fbb_helper->rotation)) {
> 	/* conflicting rotation requests on different connnectors, fall
> 	 * back to unrotated. */
> 
> 	 fb_helper->rotation == ROTATE_0
> }
> 
> Or something similar at the end of drm_setup_crtcs (plus maybe doing the
> resolve in there too). Right now that logic is split between 2 functions,
> and no comment explaining what's going on.
> 
> But not sure that's actually going to help with readability.

I was thinking of just changing the code setting the fbcon_rotate_hint
to something like this:

         switch (fb_helper->sw_rotations) {
         case DRM_MODE_ROTATE_0:
                 info->fbcon_rotate_hint = FB_ROTATE_UR;
                 break;
         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:
		/*
		 * Multiple bits are set / multiple rotations requested
		 * fbcon cannot handle separate rotation settings per
		 * output, so fallback to unrotated.
		 */
                 info->fbcon_rotate_hint = FB_ROTATE_UR;
         }

Would that work for you ?

Regards,

Hans


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