On 2019-01-10 21:16, Sam Ravnborg wrote:
Hi Peter.
(Hijacking this thread as I lost the orginal mails)
Assuming you wanted to reply to this patch? https://patchwork.kernel.org/patch/10753571/
I found an unfortunate issue while recoding plane handling to use drm_atomic_helper_check_plane_state(). The driver rotates clockwise, which is not correct. I simply fixed it (patch 1/4), but maybe that will cause regressions for unsuspecting users who simply assumed that the clockwise rotation was correct? I don't know what to do about that? Adding an option to get the old broken behavior seems useless, wouldn't it be just as easy to just fix whatever app to rotate the other way instead of adding an option somewhere?
Hm, rotation support has been added before the standard rotation property was created, and at that time I assumed rotation was clockwise (which apparently was an unwise choice). Anyway, I don't have a solution for this problem, so I'll let Nicolas decide if it's acceptable to change the rotation behavior.
I have only tested this series on sama5d3, but I did check the docs for various other chips (sama5d2, sama5d4, sam9n12, sam9g15, sam9g35 and sam9x35) supported by the driver (relevant to patch 4/4).
I wonder if, when this code path is anyway touched, could benefit from drm_rect_rotate().
It is obviously not a simple replacement, but could it be used then I hope the resulting code is simpler.
What are you referring to that goes beyond what is done in patch 3/4 in this series? After setting up the strides, the only use of src_[xywh] are to calculate the scaling factors, and for that the position is irrelevant. I.e. src_x and src_y are not used. Sure, in some theoretical sense it might be good if src_[xy] are also transformed into the rotated coordinate system along with src_[wh], but it seems a bit backwards to switch over to struct drm_rect when the interesting properties are the width and height, not the coordinates of the corners. No strong feelings on the issue though...
Cheers, Peter