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Re: [Qemu-devel] [RFC v2 23/23] 40p: Add an IBM 8514/A graphics card


From: Andreas Färber
Subject: Re: [Qemu-devel] [RFC v2 23/23] 40p: Add an IBM 8514/A graphics card
Date: Sun, 19 Jun 2011 23:38:53 +0200

Am 19.06.2011 um 21:03 schrieb Blue Swirl:

On Sun, Jun 19, 2011 at 9:40 PM, Andreas Färber <address@hidden > wrote:
Some remarks:

* TCX seems to assume that TARGET_HOST_PAGE == 4 * 1024 in the unrolled loop
in tcx_update_display(). You might want to assert that.

TCX was only used on Sparc32. Though some Ultra machines had SBus,
there the page size would be 8k (also bigger pages, but that is what
QEMU uses for TARGET_PAGE_SIZE).

Well, I wasn't saying it doesn't work presently, just pointing out that a qdev device might be instantiated by someone under circumstances not envisioned.

* The check page < page_min with page_min == -1 seems unintended in
tcx_update_display() and would have undesired effects on resetting the dirty
bit. I used page_min < 0 instead.

No, the check is correct since the type of page_min is ram_addr_t
(unsigned long).

OK

* The reset code seems wrong wrt dirty bit: after zero-ing VRAM the dirty
bit should be set, not reset. Otherwise the screen is not redrawn.

Actually reset should not touch VRAM, the screen is cleared by OpenBIOS.

tcx_reset() does do a memset on the VRAM.

In my case, I like sharing code, so I'm calling ibm8514_reset() on init to initialize registers and palette - I personally prefer a black screen during the one and a half minutes before the screen gets updated the first time.

Andreas


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