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(-)