Messages in this thread | | | Date | Wed, 12 Apr 2023 11:55:34 +0300 | Subject | Re: [PATCH] drm/omap: dsi: Fix deferred probe warnings | From | Tomi Valkeinen <> |
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On 12/04/2023 11:50, Laurent Pinchart wrote: > Hi Tony, > > Thank you for the patch. > > On Wed, Apr 12, 2023 at 10:39:53AM +0300, 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. > > How can this happen ? I assume .detach() can't be called without a > priori successful call to .attach(), that that sets dsi->dsidev.
I had a quick look, and the driver calls mipi_dsi_host_register() in probe, and mipi_dsi_host_unregister() in remove.
mipi_dsi_host_unregister() always calls mipi_dsi_detach(), but I don't think mipi_dsi_host_register() always calls attach, which happens later when the peripheral probes.
Tomi
>> Let's fix the warnings by checking for a valid dsi->dsidev. >> >> Signed-off-by: Tony Lindgren <tony@atomide.com> >> --- >> 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); >
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