Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 16 Oct 2001 07:42:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 16 Oct 2001 07:42:06 -0400 Received: from mail.ocs.com.au ([203.34.97.2]:19987 "HELO mail.ocs.com.au") by vger.kernel.org with SMTP id ; Tue, 16 Oct 2001 07:41:52 -0400 X-Mailer: exmh version 2.2 06/23/2000 with nmh-1.0.4 From: Keith Owens To: "P.Agenbag" Cc: linux-kernel@vger.kernel.org Subject: Re: P4 problems In-Reply-To: Your message of "Tue, 16 Oct 2001 12:22:19 +0200." <3BCC0A5B.846C20E8@psimation.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 16 Oct 2001 21:42:09 +1000 Message-ID: <23891.1003232529@ocs3.intra.ocs.com.au> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Oct 2001 12:22:19 +0200, "P.Agenbag" wrote: >Hi, I have P4 1,4 running on Garibaldi Intel board. Can compile and boot >the 2.4.7 kernel without problems (writing this message from the 2.4.7 >kernel). However, when trying to boot the 2.4.10 or 2.4.12 kernel, it >hangs directly as booting starts. The same hard drive transferred to an >AMD athlon 1GHz boots up perfectly, even though the kernel is compiled >for Intel P4! If nobody can point to a known bug, try this to localize the problem. =========== If a kernel hangs early in the boot process (before the console has been initialized) then printk is no use because you never see the output. There is a technique for using the video display to indicate boot progress so you can localize the problem. Reporting "my kernel hangs during boot at line nnn in routine xyz" is a lot better than "my kernel hangs during boot". The idea is to write characters direct to the video screen during booting using a macro called VIDEO_CHAR. This macro takes a character position and a single character value to be displayed. Use different positions on the screen for different levels of code and use different characters in one position to indicate which stage that level is up to. For example, with the patch below, the string EAC at hang indicates parse_options(), checksetup(). The patch below is generic, except for the definition of VIDEO_CHAR which is ix86 specific. If this patch ever becomes part of the main kernel then VIDEO_CHAR needs to be moved to an arch specific header. If any arch other than ix86 uses this technique, please mail kaos@ocs.com.au with your definition of VIDEO_CHAR. You can plant VIDEO_CHAR calls anywhere you like, up to the call to mem_init(). After mem_init has done its work and memory has been remapped, VIDEO_CHAR cannot write to video memory, it will oops. However by then the console has been initialized so you can use printk. Demonstration patch against 2.4.7. This only uses screen positions 0, 1, 2. If you want to drill down into lower level routines, just use screen positions 3 onwards. To activate the debugging, add #define DEBUG_VIDEO_CHAR to the start of init/main.c. If the machine is hanging then a zero delay is fine, if it is rebooting then you need a delay to note the characters in the top left hand corner of the screen before it reboots. #define VIDEO_CHAR_DELAY_COUNT 100000000 A value around your clock speed gives a delay of approx. 1 second. Index: 7.9/init/main.c --- 7.9/init/main.c Fri, 06 Jul 2001 09:49:24 +1000 kaos (linux-2.4/k/11_main.c 1.1.5.1.1.8.1.3 644) +++ 7.9(w)/init/main.c Sun, 22 Jul 2001 23:27:38 +1000 kaos (linux-2.4/k/11_main.c 1.1.5.1.1.8.1.3 644) @@ -80,6 +80,16 @@ extern int irda_device_init(void); #error Sorry, your GCC is too old. It builds incorrect kernels. #endif +#ifdef DEBUG_VIDEO_CHAR +#ifndef VIDEO_CHAR_DELAY_COUNT +#define VIDEO_CHAR_DELAY_COUNT 0 +#endif +/* ix86 specific */ +#define VIDEO_CHAR(c, v) { int i; *((volatile char *)(0xb8000 + 2*(c))) = (v); for (i = 0; i < VIDEO_CHAR_DELAY_COUNT; ++i) ; } +#else +#define VIDEO_CHAR(c, v) +#endif + extern char _stext, _etext; extern char *linux_banner; @@ -421,12 +431,14 @@ static void __init parse_options(char *l char *next,*quote; int args, envs; + VIDEO_CHAR(1, 'A'); if (!*line) return; args = 0; envs = 1; /* TERM is set to 'linux' by default */ next = line; while ((line = next) != NULL) { + VIDEO_CHAR(2, 'A'); quote = strchr(line,'"'); next = strchr(line, ' '); while (next != NULL && quote != NULL && quote < next) { @@ -439,9 +451,11 @@ static void __init parse_options(char *l next = strchr(next+1, ' '); } } + VIDEO_CHAR(2, 'B'); if (next != NULL) *next++ = 0; if (!strncmp(line,"init=",5)) { + VIDEO_CHAR(3, 'A'); line += 5; execute_command = line; /* In case LILO is going to boot us with default command line, @@ -452,8 +466,10 @@ static void __init parse_options(char *l args = 0; continue; } + VIDEO_CHAR(2, 'C'); if (checksetup(line)) continue; + VIDEO_CHAR(2, 'D'); /* * Then check if it's an environment variable or @@ -469,9 +485,12 @@ static void __init parse_options(char *l if (*line) argv_init[++args] = line; } + VIDEO_CHAR(2, 'E'); } + VIDEO_CHAR(1, 'B'); argv_init[args+1] = NULL; envp_init[envs+1] = NULL; + VIDEO_CHAR(1, 'C'); } @@ -530,16 +549,27 @@ asmlinkage void __init start_kernel(void * Interrupts are still disabled. Do necessary setups, then * enable them */ + VIDEO_CHAR(0, 'A'); lock_kernel(); + VIDEO_CHAR(0, 'B'); printk(linux_banner); + VIDEO_CHAR(0, 'C'); setup_arch(&command_line); + VIDEO_CHAR(0, 'D'); printk("Kernel command line: %s\n", saved_command_line); + VIDEO_CHAR(0, 'E'); parse_options(command_line); + VIDEO_CHAR(0, 'F'); trap_init(); + VIDEO_CHAR(0, 'G'); init_IRQ(); + VIDEO_CHAR(0, 'H'); sched_init(); + VIDEO_CHAR(0, 'I'); softirq_init(); + VIDEO_CHAR(0, 'J'); time_init(); + VIDEO_CHAR(0, 'K'); /* * HACK ALERT! This is early. We're enabling the console before @@ -547,8 +577,10 @@ asmlinkage void __init start_kernel(void * this. But we do want output early, in case something goes wrong. */ console_init(); + VIDEO_CHAR(0, 'L'); #ifdef CONFIG_MODULES init_modules(); + VIDEO_CHAR(0, 'M'); #endif if (prof_shift) { unsigned int size; @@ -559,10 +591,14 @@ asmlinkage void __init start_kernel(void size = prof_len * sizeof(unsigned int) + PAGE_SIZE-1; prof_buffer = (unsigned int *) alloc_bootmem(size); } + VIDEO_CHAR(0, 'N'); kmem_cache_init(); + VIDEO_CHAR(0, 'O'); sti(); + VIDEO_CHAR(0, 'P'); calibrate_delay(); + VIDEO_CHAR(0, 'Q'); #ifdef CONFIG_BLK_DEV_INITRD if (initrd_start && !initrd_below_start_ok && initrd_start < min_low_pfn << PAGE_SHIFT) { @@ -570,6 +606,7 @@ asmlinkage void __init start_kernel(void "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT); initrd_start = 0; } + VIDEO_CHAR(0, 'R'); #endif mem_init(); kmem_cache_sizes_init(); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/