Re: [Intel-gfx] [CI v2 12/12] drm/edid: add EDID block count and size helpers

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 11 Apr 2022, kernel test robot <lkp@intel.com> wrote:
> Hi Jani,
>
> I love your patch! Perhaps something to improve:
>
> [auto build test WARNING on drm-tip/drm-tip]
> [also build test WARNING on next-20220411]
> [cannot apply to drm/drm-next drm-intel/for-linux-next v5.18-rc2]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Jani-Nikula/drm-edid-low-level-EDID-block-read-refactoring-etc/20220411-175027
> base:   git://anongit.freedesktop.org/drm/drm-tip drm-tip
> config: i386-randconfig-a001-20220411 (https://download.01.org/0day-ci/archive/20220411/202204112019.U9iIZWqP-lkp@intel.com/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project c6e83f560f06cdfe8aa47b248d8bdc58f947274b)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://github.com/intel-lab-lkp/linux/commit/ba74d3cc8cc1b6ba4c34a039e797994ddbc77567
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Jani-Nikula/drm-edid-low-level-EDID-block-read-refactoring-etc/20220411-175027
>         git checkout ba74d3cc8cc1b6ba4c34a039e797994ddbc77567
>         # save the config file to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/gpu/drm/
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
>>> drivers/gpu/drm/drm_edid.c:2170:6: warning: logical not is only applied to the left hand side of this comparison [-Wlogical-not-parentheses]
>            if (!edid_extension_block_count(edid) == 0)
>                ^                                 ~~
>    drivers/gpu/drm/drm_edid.c:2170:6: note: add parentheses after the '!' to evaluate the comparison first
>            if (!edid_extension_block_count(edid) == 0)
>                ^
>                 (                                    )
>    drivers/gpu/drm/drm_edid.c:2170:6: note: add parentheses around left hand side expression to silence this warning
>            if (!edid_extension_block_count(edid) == 0)
>                ^
>                (                                )
>    1 warning generated.

Whoops, thanks for the report!

BR,
Jani.

>
>
> vim +2170 drivers/gpu/drm/drm_edid.c
>
>   2112	
>   2113	/**
>   2114	 * drm_do_get_edid - get EDID data using a custom EDID block read function
>   2115	 * @connector: connector we're probing
>   2116	 * @get_edid_block: EDID block read function
>   2117	 * @data: private data passed to the block read function
>   2118	 *
>   2119	 * When the I2C adapter connected to the DDC bus is hidden behind a device that
>   2120	 * exposes a different interface to read EDID blocks this function can be used
>   2121	 * to get EDID data using a custom block read function.
>   2122	 *
>   2123	 * As in the general case the DDC bus is accessible by the kernel at the I2C
>   2124	 * level, drivers must make all reasonable efforts to expose it as an I2C
>   2125	 * adapter and use drm_get_edid() instead of abusing this function.
>   2126	 *
>   2127	 * The EDID may be overridden using debugfs override_edid or firmware EDID
>   2128	 * (drm_load_edid_firmware() and drm.edid_firmware parameter), in this priority
>   2129	 * order. Having either of them bypasses actual EDID reads.
>   2130	 *
>   2131	 * Return: Pointer to valid EDID or NULL if we couldn't find any.
>   2132	 */
>   2133	struct edid *drm_do_get_edid(struct drm_connector *connector,
>   2134				     read_block_fn read_block,
>   2135				     void *context)
>   2136	{
>   2137		enum edid_block_status status;
>   2138		int i, invalid_blocks = 0;
>   2139		struct edid *edid, *new;
>   2140	
>   2141		edid = drm_get_override_edid(connector);
>   2142		if (edid)
>   2143			goto ok;
>   2144	
>   2145		edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
>   2146		if (!edid)
>   2147			return NULL;
>   2148	
>   2149		status = edid_block_read(edid, 0, read_block, context);
>   2150	
>   2151		edid_block_status_print(status, edid, 0);
>   2152	
>   2153		if (status == EDID_BLOCK_READ_FAIL)
>   2154			goto fail;
>   2155	
>   2156		/* FIXME: Clarify what a corrupt EDID actually means. */
>   2157		if (status == EDID_BLOCK_OK || status == EDID_BLOCK_VERSION)
>   2158			connector->edid_corrupt = false;
>   2159		else
>   2160			connector->edid_corrupt = true;
>   2161	
>   2162		if (!edid_block_status_valid(status, edid_block_tag(edid))) {
>   2163			if (status == EDID_BLOCK_ZERO)
>   2164				connector->null_edid_counter++;
>   2165	
>   2166			connector_bad_edid(connector, edid, 1);
>   2167			goto fail;
>   2168		}
>   2169	
>> 2170		if (!edid_extension_block_count(edid) == 0)
>   2171			goto ok;
>   2172	
>   2173		new = krealloc(edid, edid_size(edid), GFP_KERNEL);
>   2174		if (!new)
>   2175			goto fail;
>   2176		edid = new;
>   2177	
>   2178		for (i = 1; i < edid_block_count(edid); i++) {
>   2179			void *block = (void *)edid_block_data(edid, i);
>   2180	
>   2181			status = edid_block_read(block, i, read_block, context);
>   2182	
>   2183			edid_block_status_print(status, block, i);
>   2184	
>   2185			if (!edid_block_status_valid(status, edid_block_tag(block))) {
>   2186				if (status == EDID_BLOCK_READ_FAIL)
>   2187					goto fail;
>   2188				invalid_blocks++;
>   2189			}
>   2190		}
>   2191	
>   2192		if (invalid_blocks) {
>   2193			connector_bad_edid(connector, edid, edid_block_count(edid));
>   2194	
>   2195			edid = edid_filter_invalid_blocks(edid, invalid_blocks);
>   2196		}
>   2197	
>   2198	ok:
>   2199		return edid;
>   2200	
>   2201	fail:
>   2202		kfree(edid);
>   2203		return NULL;
>   2204	}
>   2205	EXPORT_SYMBOL_GPL(drm_do_get_edid);
>   2206	

-- 
Jani Nikula, Intel Open Source Graphics Center