We want to stop gup, which isn't the case if we use vmf_insert_page
and VM_MIXEDMAP, because that does not set pte_special.
The motivation here is to stop get_user_pages from working on buffer
object mmaps in general. Quoting some discussion with Thomas:
On Thu, Jul 22, 2021 at 08:22:43PM +0200, Thomas Zimmermann wrote:
> Am 13.07.21 um 22:51 schrieb Daniel Vetter:
> > We want to stop gup, which isn't the case if we use vmf_insert_page
>
> What is gup?
get_user_pages. It pins memory wherever it is, which badly wreaks at least
ttm and could also cause trouble with cma allocations. In both cases
becaue we can't move/reuse these pages anymore.
Now get_user_pages fails when the memory isn't considered "normal", like
with VM_PFNMAP and using vm_insert_pfn. For consistency across all dma-buf
I'm trying (together with Christian König) to roll this out everywhere,
for fewer surprises.
E.g. for 5.14 iirc we merged a patch to do the same for ttm, where it
closes an actual bug (ttm gets really badly confused when there's suddenly
pinned pages where it thought it can move them).
cma allcoations already use VM_PFNMAP (because that's what dma_mmap is
using underneath), as is anything that's using remap_pfn_range. Worst case
we have to revert this patch for shmem helpers if it breaks something, but
I hope that's not the case. On the ttm side we've also had some fallout
that we needed to paper over with clever tricks.
v2: With this shmem gem helpers now definitely need CONFIG_MMU (0day)
v3: add more depends on MMU. For usb drivers this is a bit awkward,
but really it's correct: To be able to provide a contig mapping of
buffers to userspace on !MMU platforms we'd need to use the cma
helpers for these drivers on those platforms. As-is this wont work.
Also not exactly sure why vm_insert_page doesn't go boom, because that
definitely wont fly in practice since the pages are non-contig to
begin with.
v4: Explain the entire motivation a lot more (Thomas)
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210812131412.2487363-2-daniel.vetter@ffwll.ch
The udl driver for DisplayLink devices depends on support for host-side
USB controllers, which is enabled with CONFIG_USB. Plain USB support as
given by CONFIG_USB_SUPPORT is not sufficient.
This patch changes dependencies for udl to depend on CONFIG_USB, instead
of CONFIG_USB_SUPPORT. Users will have to enable CONFIG_USB and select a
USB host controller. With this change udl dependencies work the same way
as dependencies for PCI drivers.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200106141016.9562-1-tzimmermann@suse.de
Udl's GEM code and the generic SHMEM are almost identical. Replace
the former with SHMEM. The dmabuf support in udl is being replaced
with generic GEM PRIME functions.
The main difference is in the caching flags for mmap pages. By
default, SHMEM always sets (uncached) write combining. In udl's
memory management code, only imported buffers use write combining.
Memory pages of locally created buffer objects are mmap'ed with
caching enabled. To keep the optimization, udl provides its own
mmap function for GEM objects where it fixes up the mapping flags.
v3:
- restore udl vmap that enables caching
v2:
- remove obsolete code in a separate patch
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191107094307.19870-4-tzimmermann@suse.de
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This merges all the remains of drm_usb into its only user, udl. We can
then drop all the drm_usb stuff, including dev->usbdev.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
For drivers which might want to disable fbdev legacy support.
Select the new option in all drivers for now, so this shouldn't result
in any change. Drivers need some work anyway to make fbdev support
optional (if they have it implemented, that is), so the recommended
way to expose this is by adding per-driver options. At least as long
as most drivers don't support disabling the fbdev support.
v2: Update for new drm drivers msm and rcar-du. Note that Rob's msm
driver can already take advantage of this, which allows us to build
msm without any fbdev depencies in the kernel!
v3: Move the MODULE_* stuff from the fbdev helper file to
drm_crtc_helper.c.
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Acked-by: Dave Airlie <airlied@linux.ie>
Reviewed-by: Chon Ming Lee <chon.ming.lee@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
CC: Dave Airlie <airlied@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix config warning:
warning: ( ... && DRM_USB) selects USB which has unmet direct dependencies
(USB_SUPPORT && USB_ARCH_HAS_HCD)
and build error:
ERROR: "usb_speed_string" [drivers/usb/core/usbcore.ko] undefined!
by adding the missing dependency on USB_ARCH_HAS_HCD to DRM_UDL and DRM_USB.
This exposes:
drivers/video/Kconfig:36:error: recursive dependency detected!
drivers/video/Kconfig:36: symbol FB is selected by DRM_KMS_HELPER
drivers/gpu/drm/Kconfig:28: symbol DRM_KMS_HELPER is selected by DRM_UDL
drivers/gpu/drm/udl/Kconfig:1: symbol DRM_UDL depends on USB_ARCH_HAS_HCD
drivers/usb/Kconfig:78: symbol USB_ARCH_HAS_HCD depends on USB_ARCH_HAS_OHCI
drivers/usb/Kconfig:16: symbol USB_ARCH_HAS_OHCI depends on I2C
drivers/i2c/Kconfig:5: symbol I2C is selected by FB_DDC
drivers/video/Kconfig:86: symbol FB_DDC is selected by FB_CYBER2000_DDC
drivers/video/Kconfig:385: symbol FB_CYBER2000_DDC depends on FB_CYBER2000
drivers/video/Kconfig:373: symbol FB_CYBER2000 depends on FB
which is due to drivers/usb/Kconfig:
config USB_ARCH_HAS_OHCI
...
default y if ARCH_PNX4008 && I2C
Fix by dropping I2C from the above dependency; logic is that this is not a
platform dependency but a configuration dependency: the _architecture_ still
supports USB even is I2C is not selected.
This exposes:
drivers/video/Kconfig:36:error: recursive dependency detected!
drivers/video/Kconfig:36: symbol FB is selected by DRM_KMS_HELPER
drivers/gpu/drm/Kconfig:28: symbol DRM_KMS_HELPER is selected by DRM_UDL
drivers/gpu/drm/udl/Kconfig:1: symbol DRM_UDL depends on USB_ARCH_HAS_HCD
drivers/usb/Kconfig:78: symbol USB_ARCH_HAS_HCD depends on USB_ARCH_HAS_OHCI
drivers/usb/Kconfig:17: symbol USB_ARCH_HAS_OHCI depends on MFD_TC6393XB
drivers/mfd/Kconfig:396: symbol MFD_TC6393XB depends on GPIOLIB
drivers/gpio/Kconfig:35: symbol GPIOLIB is selected by FB_VIA
drivers/video/Kconfig:1560: symbol FB_VIA depends on FB
which can be fixed by having MFD_TC6393XB select GPIOLIB instead of depending on
it.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In order to satisfy all the various Kconfig options between
USB and DRM, we need to split the USB code out into a separate module
and export symbols to it.
This fixes build problems in -next reported by sfr.
Signed-off-by: Dave Airlie <airlied@redhat.com>
This is an initial drm/kms driver for the displaylink devices.
Supports fb_defio,
supports KMS dumb interface
supports 24bpp via conversion to 16bpp, hw can do this better.
supports hot unplug using new drm core features.
On an unplug, it disables connector polling, unplugs connectors
from sysfs, unplugs fbdev layer (using Kay's API), drops all the
USB device URBs, and call the drm core to unplug the device.
This driver is based in large parts on udlfb.c so I've licensed
it under GPLv2.
Signed-off-by: Dave Airlie <airlied@redhat.com>
