Hi Iceynow,
Torsten asked me to merge your patch via drm-misc-next. I'd add the
additional cc and fixes tags that Torsten listed. Are you OK with that?
Best regards
Thomas
Am 22.02.20 um 03:43 schrieb Icenowy Zheng:
>
>
> 于 2020年2月22日 GMT+08:00 上午1:13:28, Torsten Duwe <duwe@xxxxxx> 写到:
>> On Sat, Feb 22, 2020 at 12:51:27AM +0800, Icenowy Zheng wrote:
>>> Current code tries to store the link rate (in bps, which is a big
>>> number) in a u8, which surely overflow. Then it's converted back to
>>> bandwidth code (which is thus 0) and written to the chip.
>>>
>>> The code sometimes works because the chip will automatically fallback
>> to
>>> the lowest possible DP link rate (1.62Gbps) when get the invalid
>> value.
>>> However, on the eDP panel of Olimex TERES-I, which wants 2.7Gbps
>> link,
>>> it failed.
>>>
>>> As we had already read the link bandwidth as bandwidth code in
>> earlier
>>> code (to check whether it is supported), use it when setting
>> bandwidth,
>>> instead of converting it to link rate and then converting back.
>>>
>>> Fixes: e1cff82c1097 ("drm/bridge: fix anx6345 compilation for v5.5")
>>> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
>>> ---
>>> drivers/gpu/drm/bridge/analogix/analogix-anx6345.c | 3 +--
>>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
>> b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
>>> index 56f55c53abfd..2dfa2fd2a23b 100644
>>> --- a/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
>>> +++ b/drivers/gpu/drm/bridge/analogix/analogix-anx6345.c
>>> @@ -210,8 +210,7 @@ static int anx6345_dp_link_training(struct
>> anx6345 *anx6345)
>>> if (err)
>>> return err;
>>>
>>> - dpcd[0] = drm_dp_max_link_rate(anx6345->dpcd);
>>> - dpcd[0] = drm_dp_link_rate_to_bw_code(dpcd[0]);
>>> + dpcd[0] = dp_bw;
>>
>> Why do you make this assignment and not use dp_bw directly in the call?
>
> Because the dpcd array is then written as a continous array
> back to DPCD.
>
>>
>>> err = regmap_write(anx6345->map[I2C_IDX_DPTX],
>>> SP_DP_MAIN_LINK_BW_SET_REG, dpcd[0]);
>> ^^^^^^
>>> if (err)
>>> --
>>> 2.24.1
>>
>> BTW, my version is only a bit more verbose:
>>
>> https://patchwork.freedesktop.org/patch/354344/
>>
>> Torsten
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
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