Re: [PATCH] drm/i915: fix checksum write for automated test reply

Sivakumar Thulasimani
2015-07-22T12:59:18Z

On 7/22/2015 5:30 PM, Daniel Vetter wrote:
> On Wed, Jul 22, 2015 at 03:36:48PM +0530, Sivakumar Thulasimani wrote:
>> From: "Thulasimani,Sivakumar" <sivakumar.thulasimani@intel.com>
>>
>> DP spec requires the checksum of the last block read to be written
>> when replying to TEST_EDID_READ. This patch fixes the current code
>> to do the same.
>>
>> Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
>> ---
>> drivers/gpu/drm/i915/intel_dp.c | 11 ++++++++++-
>> 1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index f1b9f93..9617d04 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -4090,9 +4090,18 @@ static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
>> intel_dp->aux.i2c_defer_count);
>> intel_dp->compliance_test_data = INTEL_DP_RESOLUTION_FAILSAFE;
>> } else {
>> + struct edid *block = intel_connector->detect_edid;
>> + uint8_t temp = intel_connector->detect_edid->extensions;
>> +
>> + /* We have to write the checksum
>> + * of the last block read
>> + */
>> + while (temp--)
>> + block++;
> block += block->extensions;
>
> instead of implementing addition by adding lots of 1? Also if you want to
> simplify computation by extracting local variables, give them a better
> name than "temp". That's somewhat ok for a reused u32 tmp for register
> read-modify-writes over lots of registers, but not really for anything
> else.
> -Daniel
>
Done. uploaded v2 with this change.
>> +
>> if (!drm_dp_dpcd_write(&intel_dp->aux,
>> DP_TEST_EDID_CHECKSUM,
>> - &intel_connector->detect_edid->checksum,
>> + &block->checksum,
>> 1))
>> DRM_DEBUG_KMS("Failed to write EDID checksum\n");
>>
>> --
>> 1.7.9.5
>>
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>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
>

--
regards,
Sivakumar