Messages in this thread | | | Date | Wed, 27 Sep 2023 14:34:43 +0800 | Subject | Re: [RESEND PATCH] driver core: Clear FWNODE_FLAG_LINKS_ADDED in device_links_purge() | From | Zhenhua Huang <> |
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On 2023/9/27 13:57, Greg KH wrote: > On Wed, Sep 27, 2023 at 10:30:10AM +0800, Zhenhua Huang wrote: >> Flag FWNODE_FLAG_LINKS_ADDED stops fwnode links creation. Current kernel >> only adds it once after fwnode links creation in fw_devlink_parse_fwnode(). >> After that even device links being purged, the flag will not be cleared. >> >> Fwnode links are converted to device links and will not be added back >> forever in normal case. Essentially if a device is registered and >> unregisted (also deleted) before it is probed (due to missing fwlink >> dependencies, abort in device_links_check_suppliers), the fwlink is not >> setup next when device is newly created again. This means the probe gets >> called without meeting all dependencies. >> >> It usuallly happens in the case of a glue driver. Of_platform_populate() >> allows us to populate subnodes. We may do it in ancestor node probing >> function, then check subnode's probing status because there may be chances >> that suppliers of subnode are not ready. We may further need to do >> of_platform_depopulate(which purges device links) and in some time >> of_platform_populate() again. Such case we miss fwnode links(so that device >> links) during second time of populating subnodes. >> >> Fix it by Clearing FWNODE_FLAG_LINKS_ADDED flag in purging device link >> func, indicates both fwnode links and device links are absent. >> >> Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com> >> --- >> drivers/base/core.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/base/core.c b/drivers/base/core.c >> index b7d7f41..2a1975d 100644 >> --- a/drivers/base/core.c >> +++ b/drivers/base/core.c >> @@ -1630,6 +1630,10 @@ static void device_links_purge(struct device *dev) >> __device_link_del(&link->kref); >> } >> >> + /* Clear flags in fwnode. Give a chance to create fwnode link again */ >> + if (dev->fwnode) >> + dev->fwnode->flags &= ~FWNODE_FLAG_LINKS_ADDED; >> + >> device_links_write_unlock(); >> } >> >> -- >> 2.7.4 >> > > Why is this a RESEND? What was wrong with the first version?
As per request of codes author, I CCed saravanak this time :) Nothing else changed.
Thanks, Zhenhua
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