| Message ID | 1377701263-3319-18-git-send-email-julien.grall@linaro.org |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Wed, 2013-08-28 at 15:47 +0100, Julien Grall wrote: > When a device has a property status with disabled inside, Linux will not use > the device. Do we not filter such devices out already? Or did the previous patch remove that functionality? In which case is there a bisection hazard here? Why is it preferred to leave the device with disabled in it instead of removing it? (Can this go in the changelog please) I think I've asked before, but is the handling of status = disabled generic and therefore reliable? > > Signed-off-by: Julien Grall <julien.grall@linaro.org> > --- > xen/arch/arm/domain_build.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c > index 76decf4..d56bc70a 100644 > --- a/xen/arch/arm/domain_build.c > +++ b/xen/arch/arm/domain_build.c > @@ -208,6 +208,14 @@ static int write_properties(struct domain *d, struct kernel_info *kinfo, > return res; > } > > + /* Disable all devices used by Xen */ > + if ( dt_device_used_by(np) == DOMID_XEN ) > + { > + res = fdt_property(kinfo->fdt, "status", "disabled", 8 + 1); > + if ( res ) > + return res; > + } > + > /* > * XXX should populate /chosen/linux,initrd-{start,end} here if we > * have module[2]
On 09/09/2013 12:37 PM, Ian Campbell wrote: > On Wed, 2013-08-28 at 15:47 +0100, Julien Grall wrote: >> When a device has a property status with disabled inside, Linux will not use >> the device. > > Do we not filter such devices out already? We only filter gic/timer node. All the others nodes used by Xen, for instance the serial device, will be marked by status = "disabled". > Or did the previous patch remove that functionality? In which case is > there a bisection hazard here? AFAIK, there is no bisection hazard with the current order of this patch series. > > Why is it preferred to leave the device with disabled in it instead of > removing it? (Can this go in the changelog please) > I think I've asked before, but is the handling of status = disabled > generic and therefore reliable? I let this patch because I didn't implement all the fake nodes in the previous patch series. In another hand, I'm not sure how Linux will react if there is a missing node and it should cope with status = "disabled" with most of nodes. I will give a try and see if I can remove completely nodes used by Xen. Except, of course, gic and timer nodes which are recreated later. >> >> Signed-off-by: Julien Grall <julien.grall@linaro.org> >> --- >> xen/arch/arm/domain_build.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c >> index 76decf4..d56bc70a 100644 >> --- a/xen/arch/arm/domain_build.c >> +++ b/xen/arch/arm/domain_build.c >> @@ -208,6 +208,14 @@ static int write_properties(struct domain *d, struct kernel_info *kinfo, >> return res; >> } >> >> + /* Disable all devices used by Xen */ >> + if ( dt_device_used_by(np) == DOMID_XEN ) >> + { >> + res = fdt_property(kinfo->fdt, "status", "disabled", 8 + 1); >> + if ( res ) >> + return res; >> + } >> + >> /* >> * XXX should populate /chosen/linux,initrd-{start,end} here if we >> * have module[2] > >
On Mon, 2013-09-09 at 22:53 +0100, Julien Grall wrote: > On 09/09/2013 12:37 PM, Ian Campbell wrote: > > On Wed, 2013-08-28 at 15:47 +0100, Julien Grall wrote: > >> When a device has a property status with disabled inside, Linux will not use > >> the device. > > > > Do we not filter such devices out already? > > We only filter gic/timer node. All the others nodes used by Xen, for > instance the serial device, will be marked by status = "disabled". Ah, the current code omits devices from the mapping but not the fdt, I was confusing the two. In the current way of doing things fdt_next_dom0_node would need a check for the owner, but that's not relevant with this series. > > Or did the previous patch remove that functionality? In which case is > > there a bisection hazard here? > > AFAIK, there is no bisection hazard with the current order of this patch > series. Ack, thanks. > > > > > Why is it preferred to leave the device with disabled in it instead of > > removing it? (Can this go in the changelog please) > > I think I've asked before, but is the handling of status = disabled > > generic and therefore reliable? > > I let this patch because I didn't implement all the fake nodes in the > previous patch series. In another hand, I'm not sure how Linux will > react if there is a missing node and it should cope with status = > "disabled" with most of nodes. > > I will give a try and see if I can remove completely nodes used by Xen. > Except, of course, gic and timer nodes which are recreated later. If you want you can add that to the end of the series/future work rather than reworking this patch in the middle of a large series.
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index 76decf4..d56bc70a 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -208,6 +208,14 @@ static int write_properties(struct domain *d, struct kernel_info *kinfo, return res; } + /* Disable all devices used by Xen */ + if ( dt_device_used_by(np) == DOMID_XEN ) + { + res = fdt_property(kinfo->fdt, "status", "disabled", 8 + 1); + if ( res ) + return res; + } + /* * XXX should populate /chosen/linux,initrd-{start,end} here if we * have module[2]
When a device has a property status with disabled inside, Linux will not use the device. Signed-off-by: Julien Grall <julien.grall@linaro.org> --- xen/arch/arm/domain_build.c | 8 ++++++++ 1 file changed, 8 insertions(+)