On 08/25/14 at 06:34am, Zheng, Lv wrote: > Hi, > > > From: Dave Young [mailto:dyoung@xxxxxxxxxx] > > Sent: Monday, August 25, 2014 2:07 PM > > To: Matt Fleming > > Cc: Zheng, Lv; Fleming, Matt; linux-efi@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; > > lenb@xxxxxxxxxx; Wysocki, Rafael J; Moore, Robert > > Subject: Re: kernel boot fail with efi earlyprintk (bisected) > > > > On 08/22/14 at 06:02pm, Dave Young wrote: > > > On 08/21/14 at 09:52pm, Matt Fleming wrote: > > > > On Tue, 19 Aug, at 04:16:58PM, Dave Young wrote: > > > > > Hi, > > > > > > > > > > 3.16 kernel boot fail with earlyprintk=efi on my laptop. > > > > > It keeps scrolling at the bottom line of screen. > > > > > > > > > > Bisected, the first bad commit is below: > > > > > commit 86dfc6f339886559d80ee0d4bd20fe5ee90450f0 > > > > > Author: Lv Zheng <lv.zheng@xxxxxxxxx> > > > > > Date: Fri Apr 4 12:38:57 2014 +0800 > > > > > > > > > > ACPICA: Tables: Fix table checksums verification before installation. > > > > > > > > > > > > > > > I did some debugging by enabling both serial and efi earlyprintk, below is > > > > > some debug dmesg, seems early_ioremap fails in scroll up function due to > > > > > no free slot, but I'm still not sure if the debug info is right or not. > > > > > > > > Thanks Dave, your callstack seems to make sense. > > > > > > > > Can you also enable early_ioremap_debug so that we can figure out where > > > > all the FIXMAP slots are going? > > > > > > With early_ioremap_debug enabled, there will be a lot of "dropped printk", so > > > I can not get any useful information. > > > > > > Will try to do more debug. > > > > early_ioremap_debug does not work because we are debugging early_printk but > > early_ioremap_debug itself will print warning message at the same time. > > > > Tried what Lv mentioned, increasing the early ioremap slots does help. > > Could you send a tested patch to linux-acpi@xxxxxxxxxxxxxxx for this? > I think the number of early mapping slots need to be increased by 1 because of this case. Problem is I do not understand the implementation detail yet. I did below changes: Original values: #define NR_FIX_BTMAPS 64 #define FIX_BTMAPS_SLOTS 4 -> new values tested: #define NR_FIX_BTMAPS 32 #define FIX_BTMAPS_SLOTS 8 There's below comments /* * 256 temporary boot-time mappings, used by early_ioremap(), * before ioremap() is functional. * * If necessary we round it up to the next 256 pages boundary so * that we can have a single pgd entry and a single pte table: */ So seems increase it to 64 * 8 = 512 should be ok. If it's fine I can test again and post a patch. Thanks Dave -- 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
