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From: | BALATON Zoltan |
Subject: | RE: Emulating Solaris 10 on SPARC64 sun4u |
Date: | Wed, 19 Feb 2020 21:10:02 +0100 (CET) |
User-agent: | Alpine 2.22 (BSF 395 2020-01-19) |
On Wed, 19 Feb 2020, BALATON Zoltan wrote:
faster or doing something differently? Does someone know what interrupts are generated on real hardware in DMA mode so we can compare that to what we see with QEMU?
The document Programming Interface for Bus Master IDE Controller, Revision 1.0 (5/16/94) has some info on this. AFAIU it says that after DMA operation is completed an IRQ should be raised. On page 5, section 3.1. Data Synchronization it says:
"Another way to view this requirement is that the first read to the controller Status register in response to the IDE device interrupt must return with the Interrupt bit set and with the guarantee that all buffered data has been written to memory."
Not sure if this is relevant but how is it handled in QEMU? Is the right interrupt bit set after DMA transfer is done? If so is it the one that's checked by the OS driver?
Regards, BALATON Zoltan
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