drm/ast: Avoid reprogramming primary-plane scanout address

Some AST-based BMCs stop display output for up to 5 seconds after
reprogramming the scanout address. As the address is fixed, avoid
re-setting the address' value.

v2:
	* only update offset if it changed (Jocelyn)

Reported-by: Jocelyn Falempe <jfalempe@redhat.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Tested-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221013112923.769-9-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann 2022-10-13 13:29:23 +02:00
parent f2fa5a99ca
commit 202fb33be3

View file

@ -671,10 +671,19 @@ static void ast_primary_plane_helper_atomic_update(struct drm_plane *plane,
ast_handle_damage(ast_plane, shadow_plane_state->data, fb, &damage);
}
ast_set_offset_reg(ast, fb);
ast_set_start_address_crt1(ast, (u32)ast_plane->offset);
ast_set_index_reg_mask(ast, AST_IO_SEQ_PORT, 0x1, 0xdf, 0x00);
/*
* Some BMCs stop scanning out the video signal after the driver
* reprogrammed the offset or scanout address. This stalls display
* output for several seconds and makes the display unusable.
* Therefore only update the offset if it changes and reprogram the
* address after enabling the plane.
*/
if (!old_fb || old_fb->pitches[0] != fb->pitches[0])
ast_set_offset_reg(ast, fb);
if (!old_fb) {
ast_set_start_address_crt1(ast, (u32)ast_plane->offset);
ast_set_index_reg_mask(ast, AST_IO_SEQ_PORT, 0x1, 0xdf, 0x00);
}
}
static void ast_primary_plane_helper_atomic_disable(struct drm_plane *plane,