From: Alvin Lee alvin.lee2@amd.com

[WHAT & HOW] According to register specifications, the CURSOR_DST_X_OFFSET is relative to the start of the data viewport, not RECOUT space. In this case we must transform the cursor coordinates passed to hubp401_cursor_set_position into viewport space to program this register. This fixes an underflow issue that occurs in scaled mode with low refresh rate.

Reviewed-by: Nevenko Stupar nevenko.stupar@amd.com Cc: Mario Limonciello mario.limonciello@amd.com Cc: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Acked-by: Alex Hung alex.hung@amd.com Signed-off-by: Alvin Lee alvin.lee2@amd.com --- .../gpu/drm/amd/display/dc/hubp/dcn401/dcn401_hubp.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/hubp/dcn401/dcn401_hubp.c b/drivers/gpu/drm/amd/display/dc/hubp/dcn401/dcn401_hubp.c index a893160ae775..3f9ca9b40949 100644 --- a/drivers/gpu/drm/amd/display/dc/hubp/dcn401/dcn401_hubp.c +++ b/drivers/gpu/drm/amd/display/dc/hubp/dcn401/dcn401_hubp.c @@ -656,7 +656,9 @@ void hubp401_cursor_set_position( int y_pos = pos->y - param->recout.y; int rec_x_offset = x_pos - pos->x_hotspot; int rec_y_offset = y_pos - pos->y_hotspot; - uint32_t dst_x_offset; + int dst_x_offset; + int x_pos_viewport = x_pos * param->viewport.width / param->recout.width; + int x_hot_viewport = pos->x_hotspot * param->viewport.width / param->recout.width; uint32_t cur_en = pos->enable ? 1 : 0;

hubp->curs_pos = *pos; @@ -668,7 +670,13 @@ void hubp401_cursor_set_position( if (hubp->curs_attr.address.quad_part == 0) return;

- dst_x_offset = (rec_x_offset >= 0) ? rec_x_offset : 0; + /* Translate the x position of the cursor from rect + * space into viewport space. CURSOR_DST_X_OFFSET + * is the offset relative to viewport start position. + */ + dst_x_offset = x_pos_viewport - x_hot_viewport * + (1 + hubp->curs_attr.attribute_flags.bits.ENABLE_MAGNIFICATION); + dst_x_offset = (dst_x_offset >= 0) ? dst_x_offset : 0; dst_x_offset *= param->ref_clk_khz; dst_x_offset /= param->pixel_clk_khz;