Messages in this thread Patch in this message | | | Date | Fri, 11 Dec 2020 18:03:15 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v2 16/17] driver core: Refactor fw_devlink feature |
| |
On 2020-12-11 17:51, Saravana Kannan wrote: > On Fri, Dec 11, 2020 at 8:34 AM Robin Murphy <robin.murphy@arm.com> > wrote: >> >> On 2020-12-11 14:11, Qian Cai wrote: >> > On Fri, 2020-11-20 at 18:02 -0800, Saravana Kannan wrote: >> >> The current implementation of fw_devlink is very inefficient because it >> >> tries to get away without creating fwnode links in the name of saving >> >> memory usage. Past attempts to optimize runtime at the cost of memory >> >> usage were blocked with request for data showing that the optimization >> >> made significant improvement for real world scenarios. >> >> >> >> We have those scenarios now. There have been several reports of boot >> >> time increase in the order of seconds in this thread [1]. Several OEMs >> >> and SoC manufacturers have also privately reported significant >> >> (350-400ms) increase in boot time due to all the parsing done by >> >> fw_devlink. >> >> >> >> So this patch uses all the setup done by the previous patches in this >> >> series to refactor fw_devlink to be more efficient. Most of the code has >> >> been moved out of firmware specific (DT mostly) code into driver core. >> >> >> >> This brings the following benefits: >> >> - Instead of parsing the device tree multiple times during bootup, >> >> fw_devlink parses each fwnode node/property only once and creates >> >> fwnode links. The rest of the fw_devlink code then just looks at these >> >> fwnode links to do rest of the work. >> >> >> >> - Makes it much easier to debug probe issue due to fw_devlink in the >> >> future. fw_devlink=on blocks the probing of devices if they depend on >> >> a device that hasn't been added yet. With this refactor, it'll be very >> >> easy to tell what that device is because we now have a reference to >> >> the fwnode of the device. >> >> >> >> - Much easier to add fw_devlink support to ACPI and other firmware >> >> types. A refactor to move the common bits from DT specific code to >> >> driver core was in my TODO list as a prerequisite to adding ACPI >> >> support to fw_devlink. This series gets that done. >> >> >> >> [1] - https://lore.kernel.org/linux-omap/ea02f57e-871d-cd16-4418-c1da4bbc4696@ti.com/ >> >> Signed-off-by: Saravana Kannan <saravanak@google.com> >> >> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> >> >> Tested-by: Grygorii Strashko <grygorii.strashko@ti.com> >> > >> > Reverting this commit and its dependency: >> > >> > 2d09e6eb4a6f driver core: Delete pointless parameter in fwnode_operations.add_links >> > >> > from today's linux-next fixed a boot crash on an arm64 Thunder X2 server. >> >> Since the call stack implicates the platform-device-wrangling we do in >> IORT code I took a quick look; AFAICS my guess would be it's blowing >> up >> trying to walk a zeroed list head since "driver core: Add >> fwnode_init()" >> missed acpi_alloc_fwnode_static(). > > Thanks Robin. I'm pretty sure this is the reason. I thought I fixed > all ACPI cases, but clearly I missed this one. I'll send out a patch > for this today. If you think there are any other places I missed > please let me know. I'll try some git grep foo to see if I missed any > other instances of fwnode ops being set.
Yup, that fixed it here (QDF2400).
Thanks,
M.
diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 39263c6b52e1..2630c2e953f7 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -55,7 +55,7 @@ static inline struct fwnode_handle *acpi_alloc_fwnode_static(void) if (!fwnode) return NULL;
- fwnode->ops = &acpi_static_fwnode_ops; + fwnode_init(fwnode, &acpi_static_fwnode_ops);
return fwnode; }
-- Jazz is not dead. It just smells funny...
| |