4.4-stable patches

added patches:
	drm-fb-helper-ignore-the-value-of-fb_var_screeninfo.pixclock.patch

diff --git a/queue-4.4/drm-fb-helper-ignore-the-value-of-fb_var_screeninfo.pixclock.patch b/queue-4.4/drm-fb-helper-ignore-the-value-of-fb_var_screeninfo.pixclock.patch
new file mode 100644 (file)
index 0000000..e98cbcb
--- /dev/null
+++ b/queue-4.4/drm-fb-helper-ignore-the-value-of-fb_var_screeninfo.pixclock.patch
@@ -0,0 +1,81 @@
+From 66a8d5bfb518f9f12d47e1d2dce1732279f9451e Mon Sep 17 00:00:00 2001
+From: Ivan Mironov <mironov.ivan@gmail.com>
+Date: Tue, 8 Jan 2019 12:23:53 +0500
+Subject: drm/fb-helper: Ignore the value of fb_var_screeninfo.pixclock
+
+From: Ivan Mironov <mironov.ivan@gmail.com>
+
+commit 66a8d5bfb518f9f12d47e1d2dce1732279f9451e upstream.
+
+Strict requirement of pixclock to be zero breaks support of SDL 1.2
+which contains hardcoded table of supported video modes with non-zero
+pixclock values[1].
+
+To better understand which pixclock values are considered valid and how
+driver should handle these values, I briefly examined few existing fbdev
+drivers and documentation in Documentation/fb/. And it looks like there
+are no strict rules on that and actual behaviour varies:
+
+       * some drivers treat (pixclock == 0) as "use defaults" (uvesafb.c);
+       * some treat (pixclock == 0) as invalid value which leads to
+         -EINVAL (clps711x-fb.c);
+       * some pass converted pixclock value to hardware (uvesafb.c);
+       * some are trying to find nearest value from predefined table
+          (vga16fb.c, video_gx.c).
+
+Given this, I believe that it should be safe to just ignore this value if
+changing is not supported. It seems that any portable fbdev application
+which was not written only for one specific device working under one
+specific kernel version should not rely on any particular behaviour of
+pixclock anyway.
+
+However, while enabling SDL1 applications to work out of the box when
+there is no /etc/fb.modes with valid settings, this change affects the
+video mode choosing logic in SDL. Depending on current screen
+resolution, contents of /etc/fb.modes and resolution requested by
+application, this may lead to user-visible difference (not always):
+image will be displayed in a right way, but it will be aligned to the
+left instead of center. There is no "right behaviour" here as well, as
+emulated fbdev, opposing to old fbdev drivers, simply ignores any
+requsts of video mode changes with resolutions smaller than current.
+
+The easiest way to reproduce this problem is to install sdl-sopwith[2],
+remove /etc/fb.modes file if it exists, and then try to run sopwith
+from console without X. At least in Fedora 29, sopwith may be simply
+installed from standard repositories.
+
+[1] SDL 1.2.15 source code, src/video/fbcon/SDL_fbvideo.c, vesa_timings
+[2] http://sdl-sopwith.sourceforge.net/
+
+Signed-off-by: Ivan Mironov <mironov.ivan@gmail.com>
+Cc: stable@vger.kernel.org
+Fixes: 79e539453b34e ("DRM: i915: add mode setting support")
+Fixes: 771fe6b912fca ("drm/radeon: introduce kernel modesetting for radeon hardware")
+Fixes: 785b93ef8c309 ("drm/kms: move driver specific fb common code to helper functions (v2)")
+Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
+Link: https://patchwork.freedesktop.org/patch/msgid/20190108072353.28078-3-mironov.ivan@gmail.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+
+---
+ drivers/gpu/drm/drm_fb_helper.c |    7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+--- a/drivers/gpu/drm/drm_fb_helper.c
++++ b/drivers/gpu/drm/drm_fb_helper.c
+@@ -1109,9 +1109,14 @@ int drm_fb_helper_check_var(struct fb_va
+       struct drm_framebuffer *fb = fb_helper->fb;
+       int depth;
+ 
+-      if (var->pixclock != 0 || in_dbg_master())
++      if (in_dbg_master())
+               return -EINVAL;
+ 
++      if (var->pixclock != 0) {
++              DRM_DEBUG("fbdev emulation doesn't support changing the pixel clock, value of pixclock is ignored\n");
++              var->pixclock = 0;
++      }
++
+       /* Need to resize the fb object !!! */
+       if (var->bits_per_pixel > fb->bits_per_pixel ||
+           var->xres > fb->width || var->yres > fb->height ||

diff --git a/queue-4.4/series b/queue-4.4/series
index d420fb63d337b80eb068139732f6c9414f1ff88f..33fad5805dcace306510258d426a5cad5b6edec1 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -68,3 +68,4 @@ block-loop-use-global-lock-for-ioctl-operation.patch
 loop-fold-__loop_release-into-loop_release.patch
 loop-get-rid-of-loop_index_mutex.patch
 loop-fix-double-mutex_unlock-loop_ctl_mutex-in-loop_control_ioctl.patch
+drm-fb-helper-ignore-the-value-of-fb_var_screeninfo.pixclock.patch