GCC complains about dubious bitwise OR operand:
drivers/gpu/drm/drm_mipi_dbi.c:1024:49: warning: dubious: x | !y
CC [M] drivers/gpu/drm/drm_mipi_dbi.o
As long as buffer is consist of byte (u8) values, we may use
simple right shift and satisfy compiler. It also reduces amount of
operations needed.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191017114912.61522-1-andriy.shevchenko@linux.intel.com
Add helper to check if a drm debug category is enabled. Convert drm core
to use it. No functional changes.
v2: Move unlikely() to drm_debug_enabled() (Eric)
v3: Keep unlikely() when combined with other conditions (Eric)
Cc: Eric Engestrom <eric@engestrom.ch>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191001140614.26909-1-jani.nikula@intel.com
- it's what we recommend in our docs:
https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#recommended-ioctl-return-values
- it's the overwhelmingly used error code for "operation not
supported", at least in drm core (slightly less so in drivers):
$ git grep EOPNOTSUPP -- drivers/gpu/drm/*c | wc -l
83
$ git grep ENOTSUPP -- drivers/gpu/drm/*c | wc -l
5
- include/linux/errno.h makes it fairly clear that these are for nfsv3
(plus they also have error codes above 512, which is the block with
some special behaviour ...)
/* Defined for the NFSv3 protocol */
If the above isn't reflecting current practice, then I guess we should
at least update the docs.
Noralf commented:
Ben Hutchings made this comment[1] in a thread about use of ENOTSUPP in
drivers:
glibc's strerror() returns these strings for ENOTSUPP and EOPNOTSUPP
respectively:
"Unknown error 524"
"Operation not supported"
So at least for errors returned to userspace EOPNOTSUPP makes sense.
José asked:
> Hopefully this will not break any userspace
None of the functions in drm_edid.c affected by this reach userspace,
it's all driver internal.
Same for the mipi function, that error code should be handled by
drivers. Drivers are supposed to remap "the hw is on fire" to EIO when
reporting up to userspace, but I think if a driver sees this it would
be a driver bug.
v2: Augment commit message with comments from Noralf and José
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Sean Paul <sean@poorly.run>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andres Rodriguez <andresx7@gmail.com>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190904143942.31756-1-daniel.vetter@ffwll.ch
This code will likely crash if we try to do a zero byte write. The code
looks like this:
/* strip trailing whitespace */
for (i = count - 1; i > 0; i--)
if (isspace(buf[i]))
...
We're writing zero bytes so count = 0. You would think that "count - 1"
would be negative one, but because "i" is unsigned it is a large
positive numer instead. The "i > 0" condition is true and the "buf[i]"
access will be out of bounds.
The fix is to make "i" signed and now everything works as expected. The
upper bound of "count" is capped in __kernel_write() at MAX_RW_COUNT so
we don't have to worry about it being higher than INT_MAX.
Fixes: 02dd95fe31 ("drm/tinydrm: Add MIPI DBI support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[noralf: Adjust title]
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190821072456.GJ26957@mwanda
This moves mipi-dbi to be a core helper with the name drm_mipi_dbi.
Fixup include's in drivers.
Move the docs entry and delete tinydrm.rst.
Delete the last tinydrm todo entry.
v2: Make DRM_MIPI_DBI tristate to enable it being built as a module.
Cc: Eric Anholt <eric@anholt.net>
Cc: David Lechner <david@lechnology.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: David Lechner <david@lechnology.com>
Acked-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190722104312.16184-9-noralf@tronnes.org
