This will be used by certain SCSI drivers to limit the length of DMA transfers
when the serial port is running at higher speeds. GVP and Phase5 DMA
interfers significantly with CPU execution, and significantly increases
receive buffer overruns (silo overflow). Reducing the DMA transfer length
can reduce the overruns.
- MIT syntax to Motorola syntax moveml register lists (for better readability)
- comment alignment
- remove commented out debug or alternate code from early DraCo support
development.
(I wanted to do this stuff for a long time, but always had "more important"
things to do.)
msgbuf. Note that old 'dmesg' and 'syslogd' binaries will continue running,
though old 'dmesg' binaries will output a few bytes of junk at the start of
the buffer, and will miss a few bytes at the end of the buffer.
NOTE: due to hardware requirement of the AGA chipset, the framebuffer width
has to be a multiple of 64 bits. An 800x600 display will use a memory width
of 832 bits, which the current X server can't handle. To get a usable
display, the width needs to be 832 or 768.
instead of bp->b_bcount. The I/O operation may have changed bp->b_bcount,
and not all of the kernel virtual memory will be freed. This will result
in the VM system putting pages back on the free list which are still
mapped. This may cause a deadlock later trying to enter pages into
the kernel pmap. [See PR#4120 for more details.]
* support chip clocks != COM_FREQ, by introducing sc_frequency (for the
mainline code) and adding a frequency parameter right after the rate
parameter to comcnattach() and com_kgdb_attach().
- Make com_isa and com_multi initialize sc_frequency to COM_FREQ.
- Make i386/machdep.c and alpha/dec_xxx.c call com*attach() with the freq.
parameter.
* supio_attach_args get two more fields: a sc_ipl and a sc_arg, both ints.
- com_supio uses the first for interupt establishment (all childs will, as
soon as they exist) and the 2nd for sc_frequency.
- drsupio passes sc_ipl alway as 5, and for the "com"s, sc_arg as 16*115200
- hyper will pass sc_ipl as 6, and sc_arg as 16 * 460800
without an 'a' partition. We open the RAW_PART partition instead.
Without this, a boot partition on the 'b' or later partition of such a disk
won't be found.
is for "standard PC i/o stuff" at known and constant locations, e.g. when
multi-io chips are used on non-ISA mainboards.
Implement drsupio.c, the DraCo version of this.
Attach the generic com.c to this bus.
Remove the old drcom hack.
mhitch