On Sunday, 25 February 2007 18:14, Andrey Borzenkov wrote: > On Воскресенье 25 февраля 2007, Rafael J. Wysocki wrote: > > On Sunday, 25 February 2007 11:37, Andrey Borzenkov wrote: > > > On Воскресенье 25 февраля 2007, Rafael J. Wysocki wrote: > > > > On Sunday, 25 February 2007 00:26, Andrey Borzenkov wrote: > > > > > On Суббота 24 февраля 2007, Rafael J. Wysocki wrote: > > > > > > Hi, > > > > > > > > > > > > On Saturday, 24 February 2007 10:55, Andrey Borzenkov wrote: > > > > > > > On Вторник 13 февраля 2007, Andrey Borzenkov wrote: > > > > > > > > On Четверг 07 декабря 2006, Lebedev, Vladimir P wrote: > > > > > > > > > Please register new bug, attach acpidump and dmesg. > > > > > > > > > > > > > > > > http://bugzilla.kernel.org/show_bug.cgi?id=7995 > > > > > > > > > > > > > > > > regards > > > > > > > > > > > > > > Well, this starts looking like ACPI is not at fault. > > > > > > > > > > > > > > When reporting AC state ACPI just reads contents of system memory > > > > > > > (I presume it gets updated by BIOS/ACPI when AC state changes). > > > > > > > It looks like this memory area is restored during resume from > > > > > > > STD. I updated mentioned bug report with more detailed > > > > > > > description. Now if someone could suggest a way to catch if > > > > > > > specific physical address gets saved/restored this would finally > > > > > > > explain it. > > > > > > > > > > > > First, if you want the reserved memory areas to be left alone by > > > > > > swsusp, you need to mark them as 'nosave'. On x86_64 this is done > > > > > > by the function e820_mark_nosave_range() in > > > > > > arch/x86_64/kernel/e820.c that can be ported to i386 with no > > > > > > problems. However, we haven't found that very useful, so far, > > > > > > since no one has ever reported any problems with the current > > > > > > approach, which is to save and restore them. > > > > > > > > > > Well, the following proof of concept patch fixes this issue for me. > > > > > Please notice that original version of e820_mark_nosave_range() could > > > > > fail to exclude some areas due to alignment issues (exactly what > > > > > happened to me on first try) so it still can explain your problem > > > > > too. > > > > > > > > Great job, thanks for the patch! It looks good, so I'm going to > > > > forward it for merging. > > > > > > Please no; I'm currently testing slightly more polished version; I will > > > send it later. > > > > OK > > > > > Could anybody explain (or give pointer to) what happens which region that > > > is not page-aligned? In particular, the very first one: > > > > > > BIOS-e820: 0000000000000000 - 000000000009fc00 (usable) > > > BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved) > > > > > > Will the kernel allocate partial page (how?) or will the kernel ignore > > > last (first) incomplete page? In the former case how those incomplete > > > pages can be detected? > > > > Well, on x86_64, if I understand e820_register_active_regions() correctly, > > the partial pages won't be registered. > > > > It appears that for low memory kernel will ignore incomplete pages for sure. I > hope it does the same for high memory - but for now I just throw this in and > pray :) You don't need to do this for highmem, because swsusp won't save reserved highmem pages anyway. > This also significantly simplifies patch. > > As this touches quite sensitive field, I Cc Andrew - if he considers this > appropriate for mm; or would you do it as part of your tree? Also he probably > can easily clarify memory allocation questions :p The patch looks good, but the changelog does not. First, AFAICT, the x86_64 code doesn't touch anything outside the e820 map. Why do you think it does? Second, it is not true that the region in question is at 0xee00 on x86_64. At least on my box it's above the end of RAM. I think the x86_64 version is correct too. Greetings, Rafael - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
