* H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> [230916 12:50]:
> Hi Tomi and Tony,
>
> > Am 13.09.2023 um 13:59 schrieb Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>:
> >
> > On 12/04/2023 10:39, Tony Lindgren wrote:
> >> We may not have dsi->dsidev initialized during probe, and that can
> >> lead into various dsi related warnings as omap_dsi_host_detach() gets
> >> called with dsi->dsidev set to NULL.
> >> The warnings can be "Fixed dependency cycle(s)" followed by a
> >> WARNING: CPU: 0 PID: 787 at drivers/gpu/drm/omapdrm/dss/dsi.c:4414.
> >> Let's fix the warnings by checking for a valid dsi->dsidev.
> >> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> >> ---
> >> drivers/gpu/drm/omapdrm/dss/dsi.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> >> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> >> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> >> @@ -4411,7 +4411,7 @@ static int omap_dsi_host_detach(struct mipi_dsi_host *host,
> >> {
> >> struct dsi_data *dsi = host_to_omap(host);
> >> - if (WARN_ON(dsi->dsidev != client))
> >> + if (dsi->dsidev && WARN_ON(dsi->dsidev != client))
> >> return -EINVAL;
> >> cancel_delayed_work_sync(&dsi->dsi_disable_work);
> >
> > Shouldn't this rather be
> >
> > if (!dsi->dsidev)
> > return 0;
> >
> > before the if (WARN_ON(dsi->dsidev != client)) line?
>
> Yes you are right. We have a different variant in our Pyra kernel:
>
> What we currently have in our Pyra tree is: https://git.goldelico.com/?p=letux-kernel.git;a=commitdiff;h=5bf7bd64eec1eb924e794e8d6600919f0dae8c5a;hp=27a0cd6263194d1465e9c53293d35f8c8c988f9d
>
> struct dsi_data *dsi = host_to_omap(host);
>
> - if (WARN_ON(dsi->dsidev != client))
> +printk("%s\n", __func__);
> +
> + if (!dsi->dsidev || WARN_ON(dsi->dsidev != client))
> return -EINVAL;
>
> cancel_delayed_work_sync(&dsi->dsi_disable_work);
>
> >
> > If dsi->dsidev is NULL, then attach hasn't been called, and we shouldn't do anything in the detach callback either.
> >
> > With your change we'll end up doing all the work in the detach callback, without ever doing their counterpart in the attach side.
>
> If useful, I can post above mentioned patch (without printk).
Sounds good to me.
Thanks,
Tony
