From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>, dri-devel@lists.freedesktop.org
Subject: Re: Panic booting qemu-system-sparc64 with bochs_drm
Date: Sat, 4 Jul 2020 15:16:47 +0100 [thread overview]
Message-ID: <1d19833f-2977-a12f-f3a9-ef0d509ef366@ilande.co.uk> (raw)
In-Reply-To: <20200704134115.GA755192@ravnborg.org>
On 04/07/2020 14:41, Sam Ravnborg wrote:
> I think what is happening is that the bochs driver request a shadow copy
> for the frambuffer. And with the change to fbops we now use the cfb_
> functions to write to the shadow framebuffer - which is not in any IO
> space. So this does not work.
>
> So maybe all we need is the fix in drm_fb_helper_dirty_blit_real().
> If you try to undo the change so fbops is set to &drm_fbdev_fb_ops,
> but keep the fix in drm_fb_helper_dirty_blit_real() how does it then
> behave?
Bingo! I just tried that and the framebuffer is now working under qemu-system-sparc64
again - thank you so much for the help! From what you said I guess
drm_fb_helper_dirty_blit_real() is responsible syncing the shadow copy?
Below is the current working diff based upon your previous one: it certainly feels
like the difference in memcpy() behaviour should be hidden away in fb_memcpy_tofb()
or similar.
diff --git a/drivers/gpu/drm/bochs/bochs_kms.c b/drivers/gpu/drm/bochs/bochs_kms.c
index 05d8373888e8..8dcc09f1ba1d 100644
--- a/drivers/gpu/drm/bochs/bochs_kms.c
+++ b/drivers/gpu/drm/bochs/bochs_kms.c
@@ -146,6 +146,7 @@ int bochs_kms_init(struct bochs_device *bochs)
bochs->dev->mode_config.preferred_depth = 24;
bochs->dev->mode_config.prefer_shadow = 0;
bochs->dev->mode_config.prefer_shadow_fbdev = 1;
+ bochs->dev->mode_config.use_cfb_for_fbdev = true;
bochs->dev->mode_config.quirk_addfb_prefer_host_byte_order = true;
bochs->dev->mode_config.funcs = &bochs_mode_funcs;
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 5609e164805f..18d89388b125 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -398,8 +398,13 @@ static void drm_fb_helper_dirty_blit_real(struct drm_fb_helper
*fb_helper,
size_t len = (clip->x2 - clip->x1) * cpp;
unsigned int y;
+ // TODO
for (y = clip->y1; y < clip->y2; y++) {
- memcpy(dst, src, len);
+ if (fb_helper->dev->mode_config.use_cfb_for_fbdev)
+ fb_memcpy_tofb(dst, src, len);
+ else
+ memcpy(dst, src, len);
+
src += fb->pitches[0];
dst += fb->pitches[0];
}
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 6c3ef49b46b3..dce9adf7d189 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -865,6 +865,15 @@ struct drm_mode_config {
*/
bool prefer_shadow_fbdev;
+ /**
+ * @use_cfb_for_fbdev:
+ *
+ * Use cfb variants of drm_fb_helper_cfb_{fillrect,copyarea,imageblit}
+ * The cfb variants are required when the CPU do not allow direct
+ * access to the framebuffer (for example sparc64)
+ */
+ bool use_cfb_for_fbdev;
+
/**
* @quirk_addfb_prefer_xbgr_30bpp:
*
> I did not find time to follow your instructions to test this myself with
> qemu - sorry.
No worries, I do appreciate that as a maintainer it can be hard to fit these things
around life, family, job etc.
ATB,
Mark.
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next prev parent reply other threads:[~2020-07-04 14:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-03 21:57 Panic booting qemu-system-sparc64 with bochs_drm Mark Cave-Ayland
2020-07-03 22:54 ` Mark Cave-Ayland
2020-07-04 7:23 ` Sam Ravnborg
2020-07-04 11:11 ` Mark Cave-Ayland
2020-07-04 13:09 ` Mark Cave-Ayland
2020-07-04 13:41 ` Sam Ravnborg
2020-07-04 14:16 ` Mark Cave-Ayland [this message]
2020-07-04 14:52 ` Sam Ravnborg
2020-07-06 19:36 ` Mark Cave-Ayland
2020-07-07 7:03 ` Gerd Hoffmann
2020-07-07 16:17 ` Mark Cave-Ayland
2020-07-07 17:38 ` Gerd Hoffmann
2020-07-07 19:52 ` Sam Ravnborg
2020-07-07 21:06 ` Mark Cave-Ayland
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