Documentation/should-fix.txt | 611 +++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 611 insertions(+) diff -puN /dev/null Documentation/should-fix.txt --- /dev/null 2002-08-30 16:31:37.000000000 -0700 +++ 25-akpm/Documentation/should-fix.txt 2003-10-03 02:15:39.000000000 -0700 @@ -0,0 +1,611 @@ +Not-ready features and speedups +=============================== + +Legend: + +PRI1: We're totally lame if this doesn't get in +PRI2: Would be nice +PRI3: Not very important + +drivers/block/ +~~~~~~~~~~~~~~ + +o Framework for selecting IO schedulers. This is the main one really. + Once this is in place we can drop in new schedulers any old time, no risk. + Nick Piggin has code for this. + + PRI1 + +o viro: paride drivers need a big cleanup + + PRI2 + +drivers/char/rtc/ +~~~~~~~~~~~~~~~~~ + +o rmk, trini: add support for alarms to the existing generic rtc driver. + + PRI2 + +console drivers +~~~~~~~~~~~~~~~ + (Pavel Machek <pavel@ucw.cz>) + +o There are few must-fix bugs in cursor handling. + +o Play with gpm selection for a while and your cursor gets corrupted with + random dots. Ouch. + +device mapper +~~~~~~~~~~~~~ + +o ioctl interface cleanup patch is ready (redo the structure layouts) + + PRI1 + +o A port of the 2.4 snapshot and mirror targets is in progress + + PRI1 + +o the fs interface to dm needs to be redone. gregkh was going to work on + this. viro is interested in seeing work thus-far. + + PRI2 + +drivers/net/wireless/ +~~~~~~~~~~~~~~~~~~~~~ + + (Jean Tourrilhes <jt@bougret.hpl.hp.com>) + +o get latest orinoco changes from David. + + PRI1 + +o get the latest airo.c fixes from CVS. This will hopefully fix problems + people have reported on the LKML. + + PRI1 + +o get HostAP driver in the kernel. No consolidation of the 802.11 + management across driver can happen until this one is in (which is probably + 2.7.X material). I think Jouni is mostly ready but didn't find time for + it. + + PRI2 + +o get more wireless drivers into the kernel. The most "integrable" drivers + at this point seem the NWN driver, Pavel's Spectrum driver and the Atmel + driver. + + PRI1 + +o The last two drivers mentioned above are held up by firmware issues (see + flamewar on LKML a few days ago). So maybe fixing those firmware issues + should be a requirement for 2.6.X, because we can expect more wireless + devices to need firmware upload at startup coming to market. + + (in progress?) + + PRI1 + +drivers/usb/gadget/ +~~~~~~~~~~~~~~~~~~~ + +o rmk: SA11xx USB client/gadget code (David B has been doing some work on + this, and keeps trying to prod me, but unfortunately I haven't had the time + to look at his work, sorry David.) + + PRI3 + +fs/ +~~~ + +o ext3 and ext2 block allocators have serious failure modes - interleaved + allocations. + + PRI3 + +o Integrate Chris Mason's 2.4 reiserfs ordered data and data journaling + patches. They make reiserfs a lot safer. + + Ordered: PRI2 + data journalled: PRI3 + +o (Trond:) Yes: I'm still working on an atomic "open()", i.e. one + where we short-circuit the usual VFS path_walk() + lookup() + + permission() + create() + .... bullsh*t... + + I have several reasons for wanting to do this (all of + them related to NFS of course, but much of the reasoning applies + to *all* networked file systems). + + 1) The above sequence is simply not atomic on *any* networked + filesystem. + + 2) It introduces a sh*tload of completely unnecessary RPC calls (why + do a 'permission' RPC call when the server is in *any* case going to + tell you whether or not this operations is allowed. Why do a + 'lookup()' when the 'create()' call can be made to tell you whether or + not a file already exists). + + 3) It is incompatible with some operations: the current create() + doesn't pass an 'EXCLUSIVE' flag down to the filesystems. + + 4) (NFS specific?) open() has very different cache consistency + requirements when compared to most other VFS operations. + + I'd very much like for something like Peter Braam's 'lookup with + intent' or (better yet) for a proper dentry->open() to be integrated with + path_walk()/open_namei(). I'm still working on the latter (Peter has + already completed the lookup with intent stuff). + + (All this is in progress, see http://www.fys.uio.no/~trondmy/src) + + (Is awaiting Pater Braam's intent patches. Applicable to CIFS) + + PRI2 (?) + +o (Chuck Lever <cel@citi.umich.edu>): NFS O_DIRECT support must be + completed. The best approach is to fall back to something like the 2.4 NFS + O_DIRECT support, which issues RPCs synchronously and uses the RPC + completion mechanism to wait for I/O completion. + + PRI2 + +o viro: cleaning up options-parsers in filesystems. (patch exists, needs + porting). + + PRI2 + +o aio: fs IO isn't async at present. suparna has restart patches, they're + in -mm. Need to get Ben to review/comment. + + PRI1. + +o drepper: various filesystems use ->pid wrongly + +kernel/ +~~~~~~~ + +o rusty: Zippel's Reference count simplification. Tricky code, but cuts + about 120 lines from module.c. Patch exists, needs stressing. + + PRI3 + +o rusty: Fix module-failed-init races by starting module "disabled". Patch + exists, requires some subsystems (ie. add_partition) to explicitly say + "make module live now". Without patch we are no worse off than 2.4 etc. + + PRI1 + +o Integrate userspace irq balancing daemon. + + PRI2 + +o kexec. Seems to work, was in -mm. + + PRI3 + +o rmk: lib/inflate.c must not use static variables (causes these to be + referenced via GOTOFF relocations in PIC decompressor. We have a PIC + decompressor to avoid having to hard code a per platform zImage link + address into the makefiles.) + + PRI2 + +o klibc merge? + + PRI2 + +mm/ +~~~ + +o objrmap: concerns over page reclaim performance at high sharing levels, + and interoperation with nonlinear mappings is hairy. + +o oxymoron's async write-error-handling patch + + PRI1 + +o dropbehind for large files + + PRI2 + +net/ +~~~~ + + (davem) + +o Real serious use of IPSEC is hampered by lack of MPLS support. MPLS is a + switching technology that works by switching based upon fixed length labels + prepended to packets. Many people use this and IPSEC to implement VPNs + over public networks, it is also used for things like traffic engineering. + + A good reference site is: + + http://www.mplsrc.com/ + + Anyways, an existing (crappy) implementation exists. I've almost + completed a rewrite, I should have something in the tree next week. + + PRI1 + +o Sometimes we generate IP fragments when it truly isn't necessary. + + The way IP fragmentation is specified, each fragment must be modulo 8 + bytes in length. So suppose the device has an MTU that is not 0 modulo 8, + ethernet even classifies in this way. 1500 == (8 * 187) + 4 + + Our IP fragmenting engine can fragment on packets that are sized within + the last modulo 8 bytes of the MTU. This happens in obscure cases, but it + does happen. + + I've proposed a fix to Alexey, whereby very late in the output path we + check the packet, if we fragmented but the data length would fit into the + MTU we unfragment the packet. + + This is low priority, because technically it creates suboptimal behavior + rather than mis-operation. + + PRI1 + +net/*/netfilter/ +~~~~~~~~~~~~~~~~ + +o Lots of misc. cleanups, which are happening slowly. + + PRI2 + +power management +~~~~~~~~~~~~~~~~ + +o PM code in mainline is currently b0rked. Fixes in -mm + + PRI1 + +o Pat and Pavel disagree over swsusp. Need to sort that out. + + PRI2 + +o Frame buffer restore codepaths (that requires some deep PCI magic) + + PRI2 + +o XFree86 hooks + + PRI2 + +o AGP restoration + + PRI2 + +o DRI restoration + + (davej/Alan: not super-critical, can crash laptop on restore. davej + looking into it.) + + PRI2 + +o IDE suspend/resume without races (Ben is looking at this a little) + + PRI2 + +o Pat: There are already CPU device structures; MTRRs should be a + dynamically registered interface of CPUs, which implies there needs + to be some other glue to know that there are MTRRs that need to be + saved/restored. + + PRI1 + +global +~~~~~~ + +o We need a kernel side API for reporting error events to userspace (could + be async to 2.6 itself) + + (Prototype core based on netlink exists) + + PRI2 + +o Kai: Introduce a sane, easy and standard way to build external modules + - make clean and make modules_install are both broken + + PRI2 + +drivers +~~~~~~~ + +o Alan: Cardbus/PCMCIA requires all Russell's stuff is merged to do + multiheader right and so on + + PRI1 + +drivers/acpi/ +~~~~~~~~~~~~~ + +o Fix acpi for all newer IBM Thinkpads see + http://bugme.osdl.org/show_bug.cgi?id=1038 for more information + +o alan: VIA APIC stuff is one bit of this, there are also some other + reports that were caused by ACPI not setting level v edge trigger some + times + + PRI1 + +o mochel: it seems the acpi irq routing code could use a serious rewrite. + + grover: The problem is the ACPI irq routing code is trying to piggyback + on the existing MPS-specific data structures, and it's generally a hack. + So yes mochel is right, but it is also purging MPS-ities from common code + as well. I've done some preliminary work in this area and it doesn't seem + to break anything (yet) but a rewrite in this area imho should not be + rushed out the door. And, I think the above bugs can be fixed w/o the + rewrite. + + PRI2 + +o mochel: ACPI suspend doesn't work. Important, not cricital. Pat is + working it. + + PRI2 + +drivers/block/ +~~~~~~~~~~~~~~ + +o Floppy is almost unusably buggy still + + akpm: we need more people to test & report. + + alan: "Floppy has worked for me since the patches that went in 2.5.69-ac + and I think -bk somewhere" + + PRI1 + +drivers/char/ +~~~~~~~~~~~~~ + + +drivers/ide/ +~~~~~~~~~~~~ + + (Alan) + +o IDE PIO has occasional unexplained PIO disk eating reports + + PRI1 + +o IDE has multiple zillions of races/hangs in 2.5 still + + PRI1 + +o IDE scsi needs rewriting + + PRI2 + +o IDE needs significant reworking to handle Simplex right + + PRI2 + +o IDE hotplug handling for 2.5 is completely broken still + + PRI2 + +o There are lots of other IDE bugs that wont go away until the taskfile + stuff is included, the locking bugs that allow any user to hang the IDE + layer in 2.5, and some other updates are forward ported. (esp. HPT372N). + + PRI1 + +drivers/isdn/ +~~~~~~~~~~~~~ + + (Kai, rmk) + +o isdn_tty locking is completely broken (cli() and friends) + + PRI2 + +o fix other drivers + + PRI2 + +o lots more cleanups, adaption to recent APIs etc + + PRI3 + +o fixup tty-based ISDN drivers which provide TIOCM* ioctls (see my recent + 3-set patch for serial stuff) + + Alternatively, we could re-introduce the fallback to driver ioctl parsing + for these if not enough drivers get updated. + + PRI3 + +drivers/net/ +~~~~~~~~~~~~ + +o davej: Either Wireless network drivers or PCMCIA broke somewhen. A + configuration that worked fine under 2.4 doesn't receive any packets. Need + to look into this more to make sure I don't have any misconfiguration that + just 'happened to work' under 2.4 + + PRI1 + +drivers/scsi/ +~~~~~~~~~~~~~ + +o jejb: qlogic - + + o Merge the feral driver. It covers all qlogic chips: 1020 all the way + up to 23xxx. http://linux-scsi.bkbits.net/scsi-isp-2.5 + + o qla2xxx: only for FC chips. Has significant build issues. hch + promises to send me a "must fix" list for this. + http://linux-scsi.bkbits.net/scsi-qla2xxx-2.5 + + PRI2 + +arch/i386/ +~~~~~~~~~~ + +o Also PC9800 merge needs finishing to the point we want for 2.6 (not all). + + PRI3 + +o davej: PAT support (for mtrr exhaustion w/ AGP) + + PRI2 + +o 2.5.x won't boot on some 440GX + + alan: Problem understood now, feasible fix in 2.4/2.4-ac. (440GX has two + IRQ routers, we use the $PIR table with the PIIX, but the 440GX doesnt use + the PIIX for its IRQ routing). Fall back to BIOS for 440GX works and Intel + concurs. + + PRI1 + +o 2.5.x doesn't handle VIA APIC right yet. + + 1. We must write the PCI_INTERRUPT_LINE + + 2. We have quirk handlers that seem to trash it. + + PRI1 + +o ACPI needs the relax patches merging to work on lots of laptops + + alan: ACPI relax stuff is in 2.4-ac, compaq workaround is in next -ac + coming. These seem to deliver the goods - toshibas now work a treat. Some + other relax bits are being discussed (assume local0 starts 0 etc) and + progress looks great. This can occur before 2.6 or during. + + PRI1 + +o ECC driver questions are not yet sorted (DaveJ is working on this) (Dan + Hollis) + + alan: ECC - I have some test bits from Dan's stuff - they need no kernel + core changes for most platforms. That means we can treat it as a random + driver merge. + + PRI3 + +o alan: 2.4 has some fixes for tsc handling bugs. One where some bioses in + SMM mode mess up our toggle on the time high/low or mangle the counter and + one where a few chips need religious use of _p for timer access and we + don't do that. This is forward porting little bits of fixup. + + ACPI HZ stuff we can't trap - a lot of ACPI is implemented as outb's + triggering SMM traps + + PRI1 + +arch/x86_64/ +~~~~~~~~~~~~ + + (Andi) + +o time handling is broken. Need to move up 2.4 time.c code. + + PRI1 + +o NMI watchdog seems to tick too fast + + PRI2 + +o not very well tested. probably more bugs lurking. + + PRI1 + +o need to coredump 64bit vsyscall code with dwarf2 + + PRI2 + +o Consider merging of Erich Focht's very clean and simple homenode NUMA + scheduler (I have my own in 2.4, but Erich's 2.5 version is much cleaner) + + PRI2 + +o Consider port of the Simple NUMA API from 2.4/homenode. + + PRI3 + +o move 64bit signal trampolines into vsyscall code and add dwarf2 for it. + (in progress) + + PRI1 + +o describe kernel assembly with dwarf2 annotations for kgdb + + PRI3 + +arch/alpha/ +~~~~~~~~~~~ + +o rth: Ptrace writes are broken. This means we can't (reliably) set + breakpoints or modify variables from gdb. + + PRI1 + +arch/arm/ +~~~~~~~~~ + +o rmk: missing raw keyboard translation tables for all ARM machines. + Haven't even looked into this at all. This could be messy since there + isn't an ARM architecture standard. I'm presently hoping that it won't be + an issue. If it does, I guess we'll see drivers/char/keyboard.c explode. + + PRI2 + +arch/others/ +~~~~~~~~~~~~ + +o SH needs resyncing, as do some other ports. SH64 needs merging. + No impact on mainstream platforms hopefully. + + PRI2 + +arch/s390/ +~~~~~~~~~ + +o A nastly memory management problem causes random crashes. These appear + to be fixed/hidden by the objrmap patch, more investigation is needed. + + PRI1 + +drivers/s390/ +~~~~~~~~~~~~~ + +o Early userspace and 64 bit dev_t will allow the removal of most of + dasd_devmap.c and dasd_genhd.c. + + PRI2 + +o The 3270 console driver needs to be replaced with a working one + (prototype is there, needs to be finished). + + PRI2 + +o Minor interface changes are pending in cio/ when the z990 machines are + out. + + PRI2 + +o Jan Glauber is working on a fix for the timer issues related to running + on virtualized CPUs (wall-clock vs. cpu time). + + PRI1 + +o a block device driver for ramdisks shared among virtual machines + + PRI3 + +o driver for crypto hardware + + PRI3 + +o 'claw' network device driver + + PRI3 + _