Am Donnerstag, 16. März 2023, 14:23:02 CET schrieb Tom Rix:
> clang reportes this error
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:2322:8: error:
> variable 'possible_crtcs' is used uninitialized whenever 'if'
> condition is false [-Werror,-Wsometimes-uninitialized]
> if (vp) {
> ^~
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:2336:36: note:
> uninitialized use occurs here
> ret = vop2_plane_init(vop2, win, possible_crtcs);
> ^~~~~~~~~~~~~~
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c:2322:4:
> note: remove the 'if' if its condition is always true
> if (vp) {
> ^~~~~~~~
>
> The else-statement changes the win->type to OVERLAY without setting the
> possible_crtcs variable. Rework the block, initialize possible_crtcs to
> 0 to remove the else-statement. Split the else-if-statement out to its
> own if-statement so the OVERLAY check will catch when the win-type has
> been changed.
>
> Fixes: 368419a2d429 ("drm/rockchip: vop2: initialize possible_crtcs properly")
> Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
> ---
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> index 03ca32cd2050..fce992c3506f 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> @@ -2301,7 +2301,7 @@ static int vop2_create_crtcs(struct vop2 *vop2)
> nvp = 0;
> for (i = 0; i < vop2->registered_num_wins; i++) {
> struct vop2_win *win = &vop2->win[i];
> - u32 possible_crtcs;
> + u32 possible_crtcs = 0;
>
> if (vop2->data->soc_id == 3566) {
> /*
> @@ -2327,12 +2327,11 @@ static int vop2_create_crtcs(struct vop2 *vop2)
> /* change the unused primary window to overlay window */
> win->type = DRM_PLANE_TYPE_OVERLAY;
> }
> - } else if (win->type == DRM_PLANE_TYPE_OVERLAY) {
> - possible_crtcs = (1 << nvps) - 1;
> - } else {
> - possible_crtcs = 0;
> }
>
> + if (win->type == DRM_PLANE_TYPE_OVERLAY)
> + possible_crtcs = (1 << nvps) - 1;
> +
After a long hard stare at the code in question, I think doing it this
way looks like the correct one, as as you mention in the commit message
the first "if" will change the win->type to OVERLAY in one case, but this
then will never be added.
Michael, do you agree/disagree?
Thanks
Heiko
https://lore.kernel.org/r/20230315090158.2442771-1-michael.riesch@xxxxxxxxxxxxxx
> ret = vop2_plane_init(vop2, win, possible_crtcs);
> if (ret) {
> drm_err(vop2->drm, "failed to init plane %s: %d\n",
>
