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diff --git a/xorg-server/hw/xfree86/doc/devel/Domain.note b/xorg-server/hw/xfree86/doc/devel/Domain.note deleted file mode 100644 index ce0812b22..000000000 --- a/xorg-server/hw/xfree86/doc/devel/Domain.note +++ /dev/null @@ -1,159 +0,0 @@ -The purpose of the changes described here is to implement a more general -framework for multi-head on systems with more than one host-to-PCI bridge. -The changes also implement a basic port of XFree86 to SPARC Solaris. - -These changes are derived from David S. Miller's submission #4653 to the -patch list. David Andrew of Sun Microsystems was also kind enough to -arrange for a hardware loan for development of these changes. - -These changes are known to work on several SPARC SunOS and UltraSPARC -Linux configurations. Linux kernel work is in progress to port these -changes to Linux/PowerPC. - -Several loose ends still need to be addressed before these changes can be -considered stable. The bulk of this note is devoted to enumerating what -remains to be done, along with other notes, broken down into various broad -categories. - -SPARC SunOS (aka Solaris) -------------------------- -- An overview of this XFree86 port is available in README.Solaris. -- The keyboard map code in hw/xfree86/os-support/sunos/sun_kbdEv.c needs - to be extended to handle more than only the sun5 keyboard I targeted it - for. Even for the sun5, the map is incomplete as several keys are not - mapped. What is there is just barely usable. -- On exit, the server will zero out /dev/fb, but that might not be the - right thing to do for all primary adapters. This does however - appear to emulate the behaviour of Sun's commercial servers. It also - eliminates the need for output drivers to save and restore video memory - contents. (They still need to save/restore the mode timing however.) - This also chimes into a long-standing XFree86 policy to not save/restore - video memory contents if the mode on entry is found to be non-VGA, a - policy several existing drivers comply with. -- The SBUS drivers (sunbw2, suncg14, suncg3, suncg6, sunffb, sunleo and - suntcx), the common layer's SBUS code and the fbdev driver have all - only been compile tested. There are likely to be Linux'isms within - them that remain to be dealt with. -- It still needs to be verified whether or not this work adversely - affected support for ix86 Solaris. - -UltraSPARC Linux ----------------- -- Although this code can be compiled using any Linux/SPARC64 kernel, it - can only run successfully using 2.4.12 or later. -- I haven't had time to sufficiently dig into XKB to properly configure it - for sun5 keyboards. Given XFree86 on Linux/SPARC has been around for a - while, it's likely someone has already done this, and I'd appreciate - receiving a copy of a working XF86Config input section. - -PowerPC Linux -------------- -- As mentioned above, kernel work is in progress to port this PCI scheme - to Linux/PowerPC. -- Aside from kernel work, the inX() and outX() definitions in compiler.h - will need to be changed to do something akin to their SPARC definitions, - i.e. consider their port argument to be a virtual address. - -Other Linux ports to multi-domain architectures ------------------------------------------------ -- Comments in os-support/bus/linuxPci.c document the kernel interface - required to port these changes. In short, Linux ports, such as Alpha - and mips, should follow SPARC and PowerPC's lead in providing support to - mmap() PCI devices through their /proc/bus/pci pseudo-files and to treat - such requests for host bridges as requests to mmap() space provided by - these bridges. - -Other OS's ----------- -- In the right hands, either linuxPci.c or sparcPci.c can be used as a - guide for what would need to be done to port this scheme to other OS's. - Perhaps the largest difference between the two (in terms of interface to - the common layer) is that the SunOS port includes internally generated - domain numbers in PCITAG's, whereas the Linux port doesn't need to. The - remainder of the PCI code (which is OS-independent) can handle either - scheme. -- Required entry points are xf86GetPciDomain(), xf86MapDomainMemory(), - xf86MapDomainIO() and xf86ReadDomainMemory(). Replacements for - xf86BusAccWindowsFromOS(), xf86PciBusAccWindowsFromOS() and - xf86AccResFromOS() might also be required. -- Development of these changes has detected the fact that the XFree86 port - to the PowerMax OS is broken, and has been for some time, i.e. since - shortly after its introduction, back in the 3.9* days. - -SPARC PCI (OS-independent) --------------------------- -- The "Simba" PCI-to-PCI bridge used in SPARC's does not implement VGA - routing, as defined in the PCI specs. Fortunately, OpenPROM seems to - always route VGA resources to the bus with PCI connectors, but this also - causes the common layer to not mark any PCI adapter as primary. - -Multiple PCI domains (architecture- and OS-independent) -------------------------------------------------------- -- This implementation assumes every host-to-PCI bridge provides access to - a separate PCI domain. Each such domain provides three different - "address" spaces: PCI configuration, I/O and memory. The - implementation can also deal with situations where more than one PCI - domain share (different subsets of) the same PCI configuration space. I - have unconfirmed information that suggests it might be necessary to also - allow the sharing of PCI memory spaces. -- This implementation also assumes the CPU's physical address space - includes the entirety of each domain's I/O and memory spaces. I know - this'll need to be changed to deal with the so-called UniNorth bridge, - found on PowerPC's, which allows access to only a subset of the memory - space behind it. -- Ideally, the common layer should mark as primary up to one PCI adapter - per domain. This has yet to be done. -- Something needs to be done about PCI master aborts on primary buses. - For details on this, see my long-winded diatribe in sparcPci.c, and - related comments in linuxPci.c. Suffice it to say here that I see the - eventual implementation of host bridge drivers within XFree86 as - unavoidable at this point. -- DGA is broken on multi-domain platforms. The information passed to the - client to locate the framebuffer still needs to be revised. The best way - to deal with this is to change all drivers' OpenFramebuffer() function to - call a common layer routine to set the device name and displacements to be - returned to the DGA client. - -Output drivers --------------- -Most drivers currently used on ix86 need(ed) source code changes. -- Calls to xf86ReadBIOS() and xf86MapVidMem() were replaced with calls to - xf86ReadDomainMemory() and xf86MapDomainMemory() respectively. Except - for the "ati" and "atimisc" modules, this has already been done. -- All ix86-style I/O port numbers need to be declared as an IOADDRESS, a - type defined in xf86Pci.h as "unsigned long". Such port numbers also - need to be offset by a displacement which is also defined as an - IOADDRESS. Before a driver's PreInit() is called, the common layer - makes this displacement available in ScrnInfoRec.domainIOBase. For - single-domain architectures, such as ix86, domainIOBase will always be - zero. Current use of vgaHWRec.PIOOffset has also been adjusted - accordingly. Some drivers have been changed to keep a copy of this - displacement in their private structure. Internally, an IOADDRESS is - actually a pointer that has been recasted to an unsigned long, but the - common layer "hides" this fact from the driver ABI, which means that I/O - port numbers, as seen by drivers, remain as integers rather than - addresses. Aside from the ati and atimisc modules, s3, sis and tseng - are the only modules left whose I/O still needs to be converted (I've - temporarily run out of steam). -- Note that these conversions are not necessarily sufficient to produce - drivers that will work on any given multi-domain architecture. A driver - that, for example, had endianness problems, still does. But, at least, - these conversions, along with the supporting common layer changes, make - PCI drivers more widely amenable to porting. -- rdinx(), wrinx(), modinx(), testrg(), testinx() and testinx2() are not - given enough information to allow for the relocation of their I/O. They - are consequently being deleted. The apm and ark drivers, the only - remaining callers of the first three, have been changed to use local - definitions instead. The last three (test*()) were already unused. -- As a temporary measure, these changes completely disable ISA-style - probing on SPARC's and PowerPC's. This means that driver calls to - xf86MatchIsaInstances(), while still valid, will always return detection - failure on SPARC's and PowerPC's. This will be dealt with when a more - general master abort handling scheme is implemented. -- I need to make a decision about the master abort issues mentionned above - before I can convert the "ati" and "atimisc" modules. Consequently, - these modules still need to be compiled with -DAVOID_CPIO on - multi-domain architectures, and support for Mach64 variants as - non-primary heads is not yet available. - -$XFree86$ |