linux-kernel - Re: [PATCH] x86: usb debug port early console

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Date:	Wed, 23 Jul 2008 13:18:12 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"Andrew Morton" <akpm@...ux-foundation.org>
Cc:	mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
	andi@...stfloor.org, arjan@...radead.org, ebiederm@...ssion.com,
	greg@...ah.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: usb debug port early console

On Wed, Jul 23, 2008 at 1:12 PM, Andrew Morton
<akpm@...ux-foundation.org> wrote:
> On Wed, 23 Jul 2008 12:52:20 -0700
> Yinghai Lu <yhlu.kernel@...il.com> wrote:
>
>>
>>
>> based on work from Eric, and add some timeout so don't dead loop when debug device
>> is not installed
>>
>>
>> ...
>>
>> +static void dbgp_mdelay(int ms)
>> +{
>> +     int i;
>> +     while (ms--) {
>> +             for (i = 0; i < 1000; i++)
>> +                     outb(0x1, 0x80);
>> +     }
>> +}
>
> hm.  port 80 has a guaranteed one microsecond?  Why not
> udelay()/mdelay()/etc?
>
>> +static void dbgp_breath(void)
>> +{
>> +     /* Sleep to give the debug port a chance to breathe */
>> +}
>
> I expect the compiler will optimise away any calls to this.
>
>>
>> ...
>>
>> --- linux-2.6.orig/arch/x86/kernel/head64.c
>> +++ linux-2.6/arch/x86/kernel/head64.c
>> @@ -72,6 +72,8 @@ static void __init copy_bootdata(char *r
>>       }
>>  }
>>
>> +extern void __init enable_debug_console(char *buf);
>
> Please always pass all patches through scripts/checkpatch.pl.
yhlu@...ux-zpir:~/xx/xx/kernel/tip/linux-2.6> ./scripts/checkpatch.pl
patches/9xxx.patch
WARNING: line over 80 characters
#319: FILE: arch/x86/kernel/early_printk.c:420:
+       if (!(read_pci_config_16(num, slot, func, PCI_STATUS) &
PCI_STATUS_CAP_LIST))

WARNING: line over 80 characters
#330: FILE: arch/x86/kernel/early_printk.c:431:
+               pos = read_pci_config_byte(num, slot, func,
pos+PCI_CAP_LIST_NEXT);

WARNING: line over 80 characters
#335: FILE: arch/x86/kernel/early_printk.c:436:
+static __u32 __init find_dbgp(int ehci_num, unsigned *rbus, unsigned
*rslot, unsigned *rfunc)

WARNING: line over 80 characters
#344: FILE: arch/x86/kernel/early_printk.c:445:
+                               class = read_pci_config(bus, slot,
func, PCI_CLASS_REVISION);

WARNING: line over 80 characters
#347: FILE: arch/x86/kernel/early_printk.c:448:
+                               cap = find_cap(bus, slot, func,
PCI_CAP_ID_EHCI_DEBUG);

WARNING: line over 80 characters
#386: FILE: arch/x86/kernel/early_printk.c:487:
+                               portsc =
readl(&ehci_regs->port_status[port - 1]);

WARNING: externs should be avoided in .c files
#425: FILE: arch/x86/kernel/early_printk.c:526:
+void early_printk(const char *fmt, ...);

WARNING: consider using strict_strtoul in preference to simple_strtoul
#518: FILE: arch/x86/kernel/early_printk.c:619:
+               dbgp_num = simple_strtoul(s, &e, 10);

WARNING: externs should be avoided in .c files
#722: FILE: arch/x86/kernel/head64.c:75:
+extern void __init enable_debug_console(char *buf);

total: 0 errors, 9 warnings, 773 lines checked

patches/9xxx.patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

YH
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