2010/3/10 Kevin O'Connor <ke...@koconnor.net>: > On Wed, Mar 10, 2010 at 11:49:48AM +0800, Roy Tam wrote: >> 2010/3/10 Kevin O'Connor <ke...@koconnor.net>: >> > SeaBIOS has a wealth of debugging information that could help solve >> > these issues. >> >> Tried this this BIOS and 2 debug logs generated. >> seabios-debug.log is booting fdos0138.img and closes QEMU after boots to >> prompt. >> seabios-debug-2.log is booting fdos0138.img and type something and >> Illegal Instruction occurred. > > I don't see an "Illegal Instruction" message. Instead, I see the > keyboard just not working. What qemu version and what command line > did you use?
latest git today. when you type fast. > > I've tracked down why keys are lost on SeaBIOS and not lost on Bochs > BIOS. The fdos0138.img code is taking over the irq handler for the > ps2 port hardware irq. When the irq fires, it reads the ps2 port for > the key data and then calls the bios irq handler assuming it will > reread the key and process it. However, SeaBIOS reads the ps2 port > status indicator and finds that there is no data pending (because the > key was already read by the fdos0138.img irq handler). > > Bochs BIOS just reads the data from the ps2 port and assumes it is for > the keyboard. SeaBIOS verifies the data being read and wont process > random data from the port. > > What the fdos0138.img image is doing is broken - once it reads the key > from the ps2 port, nothing stops a new key from being read the next > time something reads from the port. Indeed, although the keyboard > works in qemu-0.11 for fdos0138.img, if one types fast they'll see > duplicate and lost keys. > But it is how programs(Chinese/Japanese/Korean Display Systems, GW-BASIC, etc.) in the past get input from keyboard. "Consider" legacy as "broken" is wrong IMHO.
