52 lines
2.0 KiB
Diff
52 lines
2.0 KiB
Diff
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From 1d3ea28fd7da9a23e278be70c7e028fbd2b69bf3 Mon Sep 17 00:00:00 2001
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From: qihao <qihao_yewu@cmss.chinamobile.com>
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Date: Thu, 25 Jul 2024 10:29:20 +0800
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Subject: [PATCH] hw/display/bcm2835_fb: fix fb_use_offsets condition
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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cheery-pick from 345acc443905eda8008a1d328dd89b73c4a3f89e
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It is common practice when implementing double-buffering on VideoCore
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to do so by multiplying the height of the virtual buffer by the
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number of virtual screens desired (i.e., two - in the case of
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double-bufferring).
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At present, this won't work in QEMU because the logic in
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fb_use_offsets require that both the virtual width and height exceed
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their physical counterparts.
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This appears to be unintentional/a typo and indeed the comment
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states; "Experimentally, the hardware seems to do this only if the
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viewport size is larger than the physical screen". The
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viewport/virtual size would be larger than the physical size if
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either virtual dimension were larger than their physical counterparts
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and not necessarily both.
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Signed-off-by: SamJakob <me@samjakob.com>
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Message-id: 20240713160353.62410-1-me@samjakob.com
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Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
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Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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Signed-off-by: qihao_yewu <qihao_yewu@cmss.chinamobile.com>
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---
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hw/display/bcm2835_fb.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/hw/display/bcm2835_fb.c b/hw/display/bcm2835_fb.c
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index a05277674f..c45da149d9 100644
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--- a/hw/display/bcm2835_fb.c
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+++ b/hw/display/bcm2835_fb.c
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@@ -145,7 +145,7 @@ static bool fb_use_offsets(BCM2835FBConfig *config)
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* viewport size is larger than the physical screen. (It doesn't
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* prevent the guest setting this silly viewport setting, though...)
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*/
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- return config->xres_virtual > config->xres &&
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+ return config->xres_virtual > config->xres ||
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config->yres_virtual > config->yres;
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}
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--
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2.41.0.windows.1
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