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* [PATCH v2 0/4] bochs fixes and fb-helper documentation updates
@ 2018-09-06 22:18 Peter Wu
  2018-09-06 22:18 ` [PATCH v2 1/4] bochs: use drm_fb_helper_set_suspend_unlocked in suspend/resume Peter Wu
                   ` (3 more replies)
  0 siblings, 4 replies; 7+ messages in thread
From: Peter Wu @ 2018-09-06 22:18 UTC (permalink / raw)
  To: Gerd Hoffmann
  Cc: virtualization, dri-devel, linux-kernel, Noralf Trønnes

Hi,

These series tries to improve the bochs driver and update documentation based on
my brief experience with the fb-helper API. Thank you Daniel and Gerd for your
previous feedback and helpful suggestions.

Patch 2 was previously posted and is unmodified except for acked-by + rebase on
drm-misc-next (9a09a42369a4a37a959c051d8e1a1f948c1529a4). Patch 1 is a trivial
(build) fix that was missing last time.

Patch 3 converts from the legacy API to the modern drm_dev_register approach.
This seems required for the "generic" fbdev API as suggested by Daniel, but as
bochs does not implement the required "gem_prime_vmap" function, the conversion
cannot be completed for now.

Patch 4 includes some documentation updates that would have helped me during
qxl/bochs development and a warning that made me realize that "a virtual address
and that can be mmap'ed" in the documentation referred to "gem_prime_vmap". It
is to my best of understanding, so please correct me if I am wrong.

Side note: I originally tried to fix the unbind/remove crash in QXL and then
turned to bochs as it seemed simpler to learn how to work on DRM drivers.
Hopefully I manage to eventually figure out how to fix QXL. QXL is a bit
strange, it advertises PRIME "support" but it only has stub functions (including
a stub gem_prime_vmap).

After my recent patch ("qxl: fix null-pointer crash during suspend") qxl can
suspend/resume in the normal situation, but doing anything (suspend or unload)
after unbinding just fails (suspend then fails with "failed to wait on release
23 after spincount 301", unload triggers a use-after-free according to KASAN).
On the other hand, bochs passes these tests:

    # 1. s/r with unbound console
    modprobe bochs_drm
    echo 0 > /sys/class/vtconsole/vtcon1/bind
    rtcwake -s 1 -m mem
    # 2. s/r in normal sitation
    echo 1 > /sys/class/vtconsole/vtcon1/bind
    rtcwake -s 1 -m mem
    # 3. unload module (and s/r for good measure)
    echo 0 > /sys/class/vtconsole/vtcon1/bind
    rmmod bochs_drm
    rtcwake -s 1 -m mem

Kind regards,
Peter

Peter Wu (4):
  bochs: use drm_fb_helper_set_suspend_unlocked in suspend/resume
  bochs: convert to drm_fb_helper_fbdev_setup/teardown
  bochs: convert to drm_dev_register
  drm/fb-helper: improve documentation and print warnings

 drivers/gpu/drm/bochs/bochs.h       | 21 ++------
 drivers/gpu/drm/bochs/bochs_drv.c   | 46 +++++++++++------
 drivers/gpu/drm/bochs/bochs_fbdev.c | 79 +++++++----------------------
 drivers/gpu/drm/bochs/bochs_hw.c    |  2 +-
 drivers/gpu/drm/bochs/bochs_kms.c   |  7 +--
 drivers/gpu/drm/bochs/bochs_mm.c    | 74 ---------------------------
 drivers/gpu/drm/drm_fb_helper.c     | 25 ++++++---
 7 files changed, 73 insertions(+), 181 deletions(-)

-- 
2.18.0


^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2018-09-10  6:22 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-09-06 22:18 [PATCH v2 0/4] bochs fixes and fb-helper documentation updates Peter Wu
2018-09-06 22:18 ` [PATCH v2 1/4] bochs: use drm_fb_helper_set_suspend_unlocked in suspend/resume Peter Wu
2018-09-06 22:18 ` [PATCH v2 2/4] bochs: convert to drm_fb_helper_fbdev_setup/teardown Peter Wu
2018-09-06 22:18 ` [PATCH v2 3/4] bochs: convert to drm_dev_register Peter Wu
2018-09-06 22:18 ` [PATCH v2 4/4] drm/fb-helper: improve documentation and print warnings Peter Wu
2018-09-07 19:46   ` Daniel Vetter
2018-09-10  6:22     ` Gerd Hoffmann

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