From owner-freebsd-current@freebsd.org Sun Feb 24 01:28:57 2019 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 04010150BD43 for ; Sun, 24 Feb 2019 01:28:57 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "troutmask", Issuer "troutmask" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 3924A777D3; Sun, 24 Feb 2019 01:28:54 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (localhost [127.0.0.1]) by troutmask.apl.washington.edu (8.15.2/8.15.2) with ESMTPS id x1O1SpZS022340 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 23 Feb 2019 17:28:51 -0800 (PST) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.15.2/8.15.2/Submit) id x1O1SpIS022339; Sat, 23 Feb 2019 17:28:51 -0800 (PST) (envelope-from sgk) Date: Sat, 23 Feb 2019 17:28:51 -0800 From: Steve Kargl To: Warner Losh Cc: Konstantin Belousov , FreeBSD Current , Peter Holm , Mark Johnston Subject: Re: r343567 aka PAE vs non-PAE merge breaks i386 freebsd Message-ID: <20190224012851.GA21748@troutmask.apl.washington.edu> Reply-To: sgk@troutmask.apl.washington.edu References: <20190222033924.GA25285@troutmask.apl.washington.edu> <20190222060410.GA25817@troutmask.apl.washington.edu> <20190223032644.GA14058@troutmask.apl.washington.edu> <20190223091931.GE2420@kib.kiev.ua> <20190223163619.GA18805@troutmask.apl.washington.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.2 (2019-01-07) X-Rspamd-Queue-Id: 3924A777D3 X-Spamd-Bar: + Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [1.92 / 15.00]; ARC_NA(0.00)[]; HAS_REPLYTO(0.00)[sgk@troutmask.apl.washington.edu]; FROM_HAS_DN(0.00)[]; NEURAL_SPAM_SHORT(0.92)[0.924,0]; IP_SCORE(0.05)[ip: (0.11), ipnet: 128.95.0.0/16(0.17), asn: 73(0.06), country: US(-0.07)]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[washington.edu]; AUTH_NA(1.00)[]; RCPT_COUNT_FIVE(0.00)[5]; NEURAL_HAM_LONG(-0.55)[-0.550,0]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; RCVD_IN_DNSWL_MED(-0.20)[21.76.95.128.list.dnswl.org : 127.0.11.2]; MX_GOOD(-0.01)[troutmask.apl.washington.edu]; REPLYTO_ADDR_EQ_FROM(0.00)[]; NEURAL_SPAM_MEDIUM(0.80)[0.800,0]; R_SPF_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:73, ipnet:128.95.0.0/16, country:US]; FREEMAIL_CC(0.00)[gmail.com]; MID_RHS_MATCH_FROM(0.00)[] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Feb 2019 01:28:57 -0000 On Sat, Feb 23, 2019 at 12:03:58PM -0700, Warner Losh wrote: > On Sat, Feb 23, 2019 at 10:57 AM Steve Kargl < > sgk@troutmask.apl.washington.edu> wrote: > > > Supposely, the laptop only has 4 GB of memory. Not sure how > > it finds memory above 4 GB. > > > > Some older chipsets had a 'hole' in memory that they mapped the PCI bus > into and then remapped RAM in that range up above the 4GB boundary. That's > how it can find memory above 4GB when you have only 4GB of RAM. I hit it > with the PC Card stuff I did back in the day since it broke certain > heuristics I had in the code that turned out to be unwise for many reasons > (not just this one). I don't recall all the details, since it's been so > long ago. > > So I think kib@ is right when he highlights > > +0x0000000100000000 - 0x000000011ffe7fff, 536772608 bytes (131048 pages) > > as the memory, since this is indeed above the 4GB limit. It's about 128k > of 4k pages (just shy of the 131072 I'd expect), which is a surprisingly > round number. Also one that's easy to implement in hardware. So it > certainly "smells" the same... > > That's why I agree with others that hw.above4g_allow=0 is worth a shot, for > at least diagnostic purposes. This memory wasn't used before and if it's > used now by the drm drivers, and those aren't PAE safe (meaning they cope > with allocations beyond 4GB), then that's quite useful to know. Or maybe > it's a different driver hating things and stomping on video memory due to > wrap around. > > Warner Thanks for the explanation. Here's an update. TL;DR: xorg is up and running; drm-legacy-kmod seems to be unsafe/unaware of PAE. Build world/kernel, drm-legacy-kmod, minimum needed ports for xorg. Kernel is unmodified GENERIC. Reboot without setting anything in /boot/loader.conf % sysctl -a | grep above % sysctl -a | grep pae vm.pmap.pae_mode: 1 % kldload /boot/modules/i915kms.ko Black screen of death. Did not even get to running xinit. Hard reset to single user mode. # fsck -y # mount -a # vi /boot/loader.conf. (Add hw.above4g_allow=0) # sync # shutdown -r now % sysctl -a | grep above % sysctl -a | grep pae vm.pmap.pae_mode: 1 % cat /boot/loader.conf if_ath_load="YES" if_ath_pci_load="YES" cpuctl_load="YES" hw.above4g_allow=0 % kldload /boot/modules/i915kms.ko Switch to vt3, login as normal user. % startx -- -depth 24 >& ~/tmp/.x.out Xorg is up and running. Not sure why my first attempt at using hw.above4g_allow=0 did not work. Perhaps, mismatch between the xorg bits and kernel/world bits. % sysctl -a | grep mem vm.lowmem_period: 10 vm.kmem_map_free: 1669365760 vm.kmem_map_size: 41910272 vm.kmem_size_scale: 1 vm.kmem_size_max: 1711276032 vm.kmem_size_min: 12582912 vm.kmem_zmax: 65536 vm.kmem_size: 1711276032 hw.physmem: 3715489792 hw.usermem: 3592175616 hw.realmem: 4294963200 % dmesg | grep memory real memory = 4294967296 (4096 MB) avail memory = 3637673984 (3469 MB) agp0: aperture size is 256M, detected 7676k stolen memory The pre-r343567 dmesg has real memory = 4294967296 (4096 MB) avail memory = 3639914496 (3471 MB) I can live with 2 MB loss. Conclusion, drm-legacy-kmod is not PAE safe/aware. Probably want to put something in /usr/src about possible problems with new pmap.h on i386 FreeBSD. -- Steve