kernel.git/Documentation/gpu/todo.rst, branch linux-5.12.y

drm: Use USB controller's DMA mask when importing dmabufs

2021-03-11T10:11:33Z

USB devices cannot perform DMA and hence have no dma_mask set in their device structure. Therefore importing dmabuf into a USB-based driver fails, which breaks joining and mirroring of display in X11. For USB devices, pick the associated USB controller as attachment device. This allows the DRM import helpers to perform the DMA setup. If the DMA controller does not support DMA transfers, we're out of luck and cannot import. Our current USB-based DRM drivers don't use DMA, so the actual DMA device is not important. Tested by joining/mirroring displays of udl and radeon under Gnome/X11. v8: * release dmadev if device initialization fails (Noralf) * fix commit description (Noralf) v7: * fix use-before-init bug in gm12u320 (Dan) v6: * implement workaround in DRM drivers and hold reference to DMA device while USB device is in use * remove dev_is_usb() (Greg) * collapse USB helper into usb_intf_get_dma_device() (Alan) * integrate Daniel's TODO statement (Daniel) * fix typos (Greg) v5: * provide a helper for USB interfaces (Alan) * add FIXME item to documentation and TODO list (Daniel) v4: * implement workaround with USB helper functions (Greg) * use struct usb_device->bus->sysdev as DMA device (Takashi) v3: * drop gem_create_object * use DMA mask of USB controller, if any (Daniel, Christian, Noralf) v2: * move fix to importer side (Christian, Daniel) * update SHMEM and CMA helpers for new PRIME callbacks Signed-off-by: Thomas Zimmermann Fixes: 6eb0233ec2d0 ("usb: don't inherity DMA properties for USB devices") Tested-by: Pavel Machek Reviewed-by: Greg Kroah-Hartman Acked-by: Christian König Acked-by: Daniel Vetter Acked-by: Noralf Trønnes Cc: Christoph Hellwig Cc: Greg Kroah-Hartman Cc: # v5.10+ Signed-off-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20210303133229.3288-1-tzimmermann@suse.de Signed-off-by: Maarten Lankhorst

Merge tag 'docs-5.12' of git://git.lwn.net/linux

2021-02-22T18:57:46Z

Pull documentation updates from Jonathan Corbet: "It has been a relatively quiet cycle in docsland. - As promised, the minimum Sphinx version to build the docs is now 1.7, and we have dropped support for Python 2 entirely. That allowed the removal of a bunch of compatibility code. - A set of treewide warning fixups from Mauro that I applied after it became clear nobody else was going to deal with them. - The automarkup mechanism can now create cross-references from relative paths to RST files. - More translations, typo fixes, and warning fixes" * tag 'docs-5.12' of git://git.lwn.net/linux: (75 commits) docs: kernel-hacking: be more civil docs: Remove the Microsoft rhetoric Documentation/admin-guide: kernel-parameters: Update nohlt section doc/admin-guide: fix spelling mistake: "perfomance" -> "performance" docs: Document cross-referencing using relative path docs: Enable usage of relative paths to docs on automarkup docs: thermal: fix spelling mistakes Documentation: admin-guide: Update kvm/xen config option docs: Make syscalls' helpers naming consistent coding-style.rst: Avoid comma statements Documentation: /proc/loadavg: add 3 more field descriptions Documentation/submitting-patches: Add blurb about backtraces in commit messages Docs: drop Python 2 support Move our minimum Sphinx version to 1.7 Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams scripts/kernel-doc: add internal hyperlink to DOC: sections Update Documentation/admin-guide/sysctl/fs.rst docs: Update DTB format references docs: zh_CN: add iio index.rst translation docs/zh_CN: add iio ep93xx_adc.rst translation ...

drm/todo: Add entry for moving to dma_resv_lock

2021-02-09T16:16:57Z

Requested by Thomas. I think it justifies a new level, since I tried to make some forward progress on this last summer, and gave up (for now). This is very tricky. Acked-by: Thomas Zimmermann Signed-off-by: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Cc: Sumit Semwal Cc: "Christian König" Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210122133624.1751802-1-daniel.vetter@ffwll.ch (cherry picked from commit 5823cca39d585e4b4a32b1292eed0015da9c3276) Signed-off-by: Maarten Lankhorst

Documentation: Replace lkml.org links with lore

2021-01-11T19:47:38Z

Replace the lkml.org links with lore to better use a single source that's more likely to stay available long-term. Done by bash script: cvt_lkml_to_lore () { tmpfile=$(mktemp ./.cvt_links.XXXXXXX) header=$(echo $1 | sed 's@/lkml/@/lkml/headers/@') wget -qO - $header > $tmpfile if [[ $? == 0 ]] ; then link=$(grep -i '^Message-Id:' $tmpfile | head -1 | \ sed -r -e 's/^\s*Message-Id:\s*<\s*//' -e 's/\s*>\s*$//' -e 's@^@https://lore.kernel.org/r/@') # echo "testlink: $link" if [ -n "$link" ] ; then wget -qO - $link > /dev/null if [[ $? == 0 ]] ; then echo $link fi fi fi rm -f $tmpfile } git grep -P -o "\bhttps?://(?:www.)?lkml.org/lkml[\/\w]+" $@ | while read line ; do echo $line file=$(echo $line | cut -f1 -d':') link=$(echo $line | cut -f2- -d':') newlink=$(cvt_lkml_to_lore $link) if [[ -n "$newlink" ]] ; then sed -i -e "s#\b$link\b#$newlink#" $file fi done Link: https://lore.kernel.org/patchwork/patch/1265849/#1462688 Signed-off-by: Joe Perches Link: https://lore.kernel.org/r/77cdb7f32cfb087955bfc3600b86c40bed5d4104.camel@perches.com Signed-off-by: Jonathan Corbet

drm/docs: Fix todo.rst

2020-11-18T10:51:58Z

I didnt' format the thing correctly :-( Fixes: 39aead8373b3 ("fbcon: Disable accelerated scrolling") Reviewed-by: Simon Ser Reported-by: Stephen Rothwell Cc: Stephen Rothwell Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20201118073637.597206-1-daniel.vetter@ffwll.ch

fbcon: Disable accelerated scrolling

2020-11-17T10:00:29Z

So ever since syzbot discovered fbcon, we have solid proof that it's full of bugs. And often the solution is to just delete code and remove features, e.g. 50145474f6ef ("fbcon: remove soft scrollback code"). Now the problem is that most modern-ish drivers really only treat fbcon as an dumb kernel console until userspace takes over, and Oops printer for some emergencies. Looking at drm drivers and the basic vesa/efi fbdev drivers shows that only 3 drivers support any kind of acceleration: - nouveau, seems to be enabled by default - omapdrm, when a DMM remapper exists using remapper rewriting for y/xpanning - gma500, but that is getting deleted now for the GTT remapper trick, and the accelerated copyarea never set the FBINFO_HWACCEL_COPYAREA flag, so unused (and could be deleted already I think). No other driver supportes accelerated fbcon. And fbcon is the only user of this accel code (it's not exposed as uapi through ioctls), which means we could garbage collect fairly enormous amounts of code if we kill this. Plus because syzbot only runs on virtual hardware, and none of the drivers for that have acceleration, we'd remove a huge gap in testing. And there's no other even remotely comprehensive testing aside from syzbot. This patch here just disables the acceleration code by always redrawing when scrolling. The plan is that once this has been merged for well over a year in released kernels, we can start to go around and delete a lot of code. v2: - Drop a few more unused local variables, somehow I missed the compiler warnings (Sam) - Fix typo in comment (Jiri) - add a todo entry for the cleanup (Thomas) v3: Remove more unused variables (0day) Reviewed-by: Tomi Valkeinen Reviewed-by: Thomas Zimmermann Reviewed-by: Greg Kroah-Hartman Acked-by: Sam Ravnborg Cc: Jiri Slaby Cc: Bartlomiej Zolnierkiewicz Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Ben Skeggs Cc: nouveau@lists.freedesktop.org Cc: Tomi Valkeinen Cc: Daniel Vetter Cc: Jiri Slaby Cc: "Gustavo A. R. Silva" Cc: Tetsuo Handa Cc: Peilin Ye Cc: George Kennedy Cc: Nathan Chancellor Cc: Peter Rosin Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20201029132229.4068359-1-daniel.vetter@ffwll.ch

drm/fb_helper: Support framebuffers in I/O memory

2020-11-09T08:20:00Z

At least sparc64 requires I/O-specific access to framebuffers. This patch updates the fbdev console accordingly. For drivers with direct access to the framebuffer memory, the callback functions in struct fb_ops test for the type of memory and call the rsp fb_sys_ of fb_cfb_ functions. Read and write operations are implemented internally by DRM's fbdev helper. For drivers that employ a shadow buffer, fbdev's blit function retrieves the framebuffer address as struct dma_buf_map, and uses dma_buf_map interfaces to access the buffer. The bochs driver on sparc64 uses a workaround to flag the framebuffer as I/O memory and avoid a HW exception. With the introduction of struct dma_buf_map, this is not required any longer. The patch removes the rsp code from both, bochs and fbdev. v7: * use min_t(size_t,) (kernel test robot) * return the number of bytes read/written, if any (fbdev testcase) v5: * implement fb_read/fb_write internally (Daniel, Sam) v4: * move dma_buf_map changes into separate patch (Daniel) * TODO list: comment on fbdev updates (Daniel) Signed-off-by: Thomas Zimmermann Reviewed-by: Daniel Vetter Reviewed-by: Sam Ravnborg Tested-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-11-tzimmermann@suse.de

drm/gem: Use struct dma_buf_map in GEM vmap ops and convert GEM backends

2020-11-09T08:19:24Z

This patch replaces the vmap/vunmap's use of raw pointers in GEM object functions with instances of struct dma_buf_map. GEM backends are converted as well. For most of them, this simply changes the returned type. TTM-based drivers now return information about the location of the memory, either system or I/O memory. GEM VRAM helpers and qxl now use ttm_bo_vmap() et al. Amdgpu, nouveau and radeon use drm_gem_ttm_vmap() et al instead of implementing their own vmap callbacks. v7: * init QXL cursor to mapped BO buffer (kernel test robot) v5: * update vkms after switch to shmem v4: * use ttm_bo_vmap(), drm_gem_ttm_vmap(), et al. (Daniel, Christian) * fix a trailing { in drm_gem_vmap() * remove several empty functions instead of converting them (Daniel) * comment uses of raw pointers with a TODO (Daniel) * TODO list: convert more helpers to use struct dma_buf_map Signed-off-by: Thomas Zimmermann Acked-by: Christian König Tested-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-7-tzimmermann@suse.de

drm/doc: Document legacy_cursor_update better

2020-10-27T09:36:45Z

It's the horror and shouldn't be used. Realized we're not clear on this in a discussion with Rob about what msm is doing to better support async commits. v2: Refine existing todo item to include this (Thomas) Cc: Sean Paul Cc: Rob Clark Acked-by: Rob Clark Signed-off-by: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20201023123925.2374863-3-daniel.vetter@ffwll.ch

drm: update todo.rst

2020-09-29T16:52:30Z

- debugfs cleanup has moved forward thanks to the cleanup Wambui has done Acked-by: Melissa Wen Reviewed-by: Greg Kroah-Hartman Cc: Wambui Karuga Cc: Greg Kroah-Hartman Cc: Melissa Wen Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200929150333.3441576-1-daniel.vetter@ffwll.ch