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Diffstat (limited to 'results/classifier/gemma3:12b/peripherals/1608802')
| -rw-r--r-- | results/classifier/gemma3:12b/peripherals/1608802 | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/results/classifier/gemma3:12b/peripherals/1608802 b/results/classifier/gemma3:12b/peripherals/1608802 new file mode 100644 index 000000000..3fbfeace2 --- /dev/null +++ b/results/classifier/gemma3:12b/peripherals/1608802 @@ -0,0 +1,50 @@ + +READ_DMA (0xC8) command does not work correctly + +The QEMU PC emulation of DMA does not behave like real hardware or other virtualization software. + +From the original bug report (Benjamin David Lunt): + + Back to the READ_DMA command, it is my conclusion that the + READ_DMA command, more precisely, the BUS Master part of QEMU is + in error. The tests that people have done to see if it works, is + probably the guest finding out that DMA doesn't work and defaulting + to PIO, but since the read was successful visually to the user, the + user assumed the READ_DMA command works, where the guest actually + defaulted back to PIO transfers without notice. + + My code works on real hardware (numerous machines), Bochs, and Oracle's + Virtual Box. + + ... + + I have a small test suite, zipped and included at: + www.fysnet.net/temp/c8bug.zip + + Within this zip file is a.img. This is a freeDOS bootable + floppy. Emulate it with QEMU and then at the DOS prompt, run + c8bug.exe. + + It will say that the drive is not ready. + "Drive never became ready" + (along with a few other lines of text) + + The source for this test suite is also included. + c8bug.c is the c source code + c8bug.h is the header file + ctype.h is a quick way to get 'bit8u' type defines + timer.h is a delay routine from another project I have + (The base IO addresses are assumed and set at the top of c8bug.c) + (compiled with DJGPP for DPMI) + + q.bat is my command line for QEMU + + On all other machines and VirtualBox, the controller is ready + for me to receive the sector data. + "Drive is ready to transmit data..." + + However, in QEMU, the controller never becomes ready. + "Drive never became ready" + +The bug was reported for QEMU for Windows, but I can confirm that QEMU for Linux also shows that +behaviour, while VirtualBox works. \ No newline at end of file |