Messages in this thread | | | Date | Mon, 12 Feb 2007 21:35:57 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH mm] cfag12864b: fix crash when built-in and no parport present |
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On Sat, 10 Feb 2007 20:51:23 +0100 Miguel Ojeda <maxextreme@gmail.com> wrote:
> Andrew, Daniel who reported the crash has tested this patch and says that it works fine avoiding it, so you can merge. > > drivers-add-lcd-support-fix-crash-when-built-in-and-no-parport-present.patch > Signed-off-by: Miguel Ojeda Sandonis <maxextreme@gmail.com> > --- > diff --git a/drivers/auxdisplay/cfag12864b.c b/drivers/auxdisplay/cfag12864b.c > index 889583d..cb44cb4 100644 > --- a/drivers/auxdisplay/cfag12864b.c > +++ b/drivers/auxdisplay/cfag12864b.c > @@ -312,6 +312,17 @@ EXPORT_SYMBOL_GPL(cfag12864b_disable); > EXPORT_SYMBOL_GPL(cfag12864b_isenabled); > > /* > + * Is the module inited? > + */ > + > +static unsigned char cfag12864b_inited; > +unsigned char cfag12864b_isinited(void) > +{ > + return cfag12864b_inited; > +} > +EXPORT_SYMBOL_GPL(cfag12864b_isinited); > + > +/* > * Module Init & Exit > */ > > @@ -319,6 +330,13 @@ static int __init cfag12864b_init(void) > { > int ret = -EINVAL; > > + /* ks0108_init() must be called first */ > + if (!ks0108_isinited()) { > + printk(KERN_ERR CFAG12864B_NAME ": ERROR: " > + "ks0108 is not initialized\n"); > + goto none; > + } > + > if (PAGE_SIZE < CFAG12864B_SIZE) { > printk(KERN_ERR CFAG12864B_NAME ": ERROR: " > "page size (%i) < cfag12864b size (%i)\n", > @@ -354,6 +372,7 @@ static int __init cfag12864b_init(void) > cfag12864b_clear(); > cfag12864b_on(); > > + cfag12864b_inited = 1; > return 0; > > cachealloced: > diff --git a/drivers/auxdisplay/cfag12864bfb.c b/drivers/auxdisplay/cfag12864bfb.c > index 94765e7..66fafbb 100644 > --- a/drivers/auxdisplay/cfag12864bfb.c > +++ b/drivers/auxdisplay/cfag12864bfb.c > @@ -137,7 +137,14 @@ static struct platform_device *cfag12864 > > static int __init cfag12864bfb_init(void) > { > - int ret; > + int ret = -EINVAL; > + > + /* cfag12864b_init() must be called first */ > + if (!cfag12864b_isinited()) { > + printk(KERN_ERR CFAG12864BFB_NAME ": ERROR: " > + "cfag12864b is not initialized\n"); > + goto none; > + } > > if (cfag12864b_enable()) { > printk(KERN_ERR CFAG12864BFB_NAME ": ERROR: " > @@ -162,6 +169,7 @@ static int __init cfag12864bfb_init(void > } > } > > +none: > return ret; > } > > diff --git a/drivers/auxdisplay/ks0108.c b/drivers/auxdisplay/ks0108.c > index a637575..e6c3646 100644 > --- a/drivers/auxdisplay/ks0108.c > +++ b/drivers/auxdisplay/ks0108.c > @@ -111,6 +111,17 @@ EXPORT_SYMBOL_GPL(ks0108_address); > EXPORT_SYMBOL_GPL(ks0108_page); > > /* > + * Is the module inited? > + */ > + > +static unsigned char ks0108_inited; > +unsigned char ks0108_isinited(void) > +{ > + return ks0108_inited; > +} > +EXPORT_SYMBOL_GPL(ks0108_isinited); > + > +/* > * Module Init & Exit > */ > > @@ -142,6 +153,7 @@ static int __init ks0108_init(void) > goto registered; > } > > + ks0108_inited = 1; > return 0; > > registered: > diff --git a/include/linux/cfag12864b.h b/include/linux/cfag12864b.h > index 0bc45e6..1605dd8 100644 > --- a/include/linux/cfag12864b.h > +++ b/include/linux/cfag12864b.h > @@ -73,5 +73,10 @@ extern void cfag12864b_disable(void); > */ > extern unsigned char cfag12864b_isenabled(void); > > +/* > + * Is the module inited? > + */ > +extern unsigned char cfag12864b_isinited(void); > + > #endif /* _CFAG12864B_H_ */ > > diff --git a/include/linux/ks0108.h b/include/linux/ks0108.h > index 8047d4b..a2c54ac 100644 > --- a/include/linux/ks0108.h > +++ b/include/linux/ks0108.h > @@ -43,4 +43,7 @@ extern void ks0108_address(unsigned char > /* Set the controller's current page (0..7) */ > extern void ks0108_page(unsigned char page); > > +/* Is the module inited? */ > +extern unsigned char ks0108_isinited(void); > + > #endif /* _KS0108_H_ */
This looks hacky.
Your patch didn't include a description of the bug (please always include such a description) so I'm not sure what's going on here. But I'm suspecting that module dependencies and appropriate choice of initcall levels is the right way to fix whatever bug this is.
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