| Message ID | 1444926315-29106-1-git-send-email-wuninsu@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 15/10/15 17:25, Insu Yun wrote: > Internally, xenbus_printf uses memory allocation, so it can be failed in > memory pressure.Therefore, xenbus_printf's return should be checked > and properly handled. [...] > --- a/drivers/input/misc/xen-kbdfront.c > +++ b/drivers/input/misc/xen-kbdfront.c > @@ -129,8 +129,11 @@ static int xenkbd_probe(struct xenbus_device *dev, > > if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0) > abs = 0; > - if (abs) > - xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1"); > + if (abs) { > + ret = xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1"); > + if (ret) > + pr_warning("xenkbd: can't request abs-pointer"); I think you want abs = 0 here or input device will be configured as absolute but the backend will supply relative coordinates. David -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Insu, On 15/10/15 19:12, Insu Yun wrote: > > > On Thu, Oct 15, 2015 at 12:40 PM, David Vrabel <david.vrabel@citrix.com > <mailto:david.vrabel@citrix.com>> wrote: > > On 15/10/15 17:25, Insu Yun wrote: > > Internally, xenbus_printf uses memory allocation, so it can be failed in > > memory pressure.Therefore, xenbus_printf's return should be checked > > and properly handled. > [...] > > --- a/drivers/input/misc/xen-kbdfront.c > > +++ b/drivers/input/misc/xen-kbdfront.c > > @@ -129,8 +129,11 @@ static int xenkbd_probe(struct xenbus_device *dev, > > > > if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0) > > abs = 0; > > - if (abs) > > - xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1"); > > + if (abs) { > > + ret = xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1"); > > + if (ret) > > > + pr_warning("xenkbd: can't request abs-pointer"); > > > This error handling is from other code . > I am not sure that it is right error handling. > > > > I think you want abs = 0 here or input device will be configured as > absolute but the backend will supply relative coordinates. > > > I cannot understand If the frontend is not able to write the node "request-abs-pointer" in the xenstore, the backend will always supply relative coordinates. Although, as abs = 1, the frontend will be configured to handle absolute coordinate. So the backend and frontend won't be able to understand each other. So you have to set abs to 0 if xebus_printf fails. Regards,
diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c index 23d0549..a3b0940 100644 --- a/drivers/input/misc/xen-kbdfront.c +++ b/drivers/input/misc/xen-kbdfront.c @@ -129,8 +129,11 @@ static int xenkbd_probe(struct xenbus_device *dev, if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0) abs = 0; - if (abs) - xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1"); + if (abs) { + ret = xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1"); + if (ret) + pr_warning("xenkbd: can't request abs-pointer"); + } /* keyboard */ kbd = input_allocate_device();
Internally, xenbus_printf uses memory allocation, so it can be failed in memory pressure.Therefore, xenbus_printf's return should be checked and properly handled. Signed-off-by: Insu Yun <wuninsu@gmail.com> --- drivers/input/misc/xen-kbdfront.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)