On Fri, Jul 23, 2021 at 6:31 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> On 7/23/21 8:15 AM, Karol Herbst wrote:
> > On Fri, Jul 23, 2021 at 5:10 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> >>
> >> On 7/23/21 2:15 AM, Arnd Bergmann wrote:
> >>> From: Arnd Bergmann <arnd@xxxxxxxx>
> >>>
> >>> When the backlight support is disabled, the driver fails to build:
> >>>
> >>> drivers/gpu/drm/nouveau/dispnv50/disp.c: In function 'nv50_sor_atomic_disable':
> >>> drivers/gpu/drm/nouveau/dispnv50/disp.c:1665:59: error: 'struct nouveau_connector' has no member named 'backlight'
> >>> 1665 | struct nouveau_backlight *backlight = nv_connector->backlight;
> >>> | ^~
> >>> drivers/gpu/drm/nouveau/dispnv50/disp.c:1670:35: error: invalid use of undefined type 'struct nouveau_backlight'
> >>> 1670 | if (backlight && backlight->uses_dpcd) {
> >>> | ^~
> >>> drivers/gpu/drm/nouveau/dispnv50/disp.c:1671:64: error: invalid use of undefined type 'struct nouveau_backlight'
> >>> 1671 | ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
> >>> | ^~
> >>>
> >>> The patch that introduced the problem already contains some #ifdef
> >>> checks, so just add another one that makes it build again.
> >>>
> >>> Fixes: 6eca310e8924 ("drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau")
> >>> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> >>> ---
> >>> drivers/gpu/drm/nouveau/dispnv50/disp.c | 11 +++++++----
> >>> 1 file changed, 7 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> >>> index 093e1f7163b3..fcf53e24db21 100644
> >>> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> >>> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> >>> @@ -1659,20 +1659,23 @@ static void
> >>> nv50_sor_atomic_disable(struct drm_encoder *encoder, struct drm_atomic_state *state)
> >>> {
> >>> struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
> >>> - struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
> >>> struct nouveau_crtc *nv_crtc = nouveau_crtc(nv_encoder->crtc);
> >>> struct nouveau_connector *nv_connector = nv50_outp_get_old_connector(state, nv_encoder);
> >>> - struct nouveau_backlight *backlight = nv_connector->backlight;
> >>> struct drm_dp_aux *aux = &nv_connector->aux;
> >>> - int ret;
> >>> u8 pwr;
> >>>
> >>> +#ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT
> >>> + struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
> >>> + struct nouveau_backlight *backlight = nv_connector->backlight;
> >>> +
> >>> if (backlight && backlight->uses_dpcd) {
> >>> - ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
> >>> + int ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
> >>> +
> >>> if (ret < 0)
> >>> NV_ERROR(drm, "Failed to disable backlight on [CONNECTOR:%d:%s]: %d\n",
> >>> nv_connector->base.base.id, nv_connector->base.name, ret);
> >>> }
> >>> +#endif
> >>>
> >>> if (nv_encoder->dcb->type == DCB_OUTPUT_DP) {
> >>> int ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
> >>>
> >>
> >> Hm, only Lyude Paul replied to this patch:
> >>
> >> https://lore.kernel.org/lkml/20210714171523.413-1-rdunlap@xxxxxxxxxxxxx/
> >>
> >
> > what's actually the use case of compiling with
> > CONFIG_DRM_NOUVEAU_BACKLIGHT=n anyway?
>
> Dunno. In this case it was just a randconfig. Still, it needs to be
> handled in some way - such as the other suggestion in this thread.
>
sure, I was just curious if there was a specific use case or just
something random as you mentioned.
