From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Sledge Subject: DRM Inquiry DPCD Date: Wed, 23 May 2018 02:42:53 +0000 (UTC) Message-ID: <1276988254.133081.1527043373244@mail.yahoo.com> References: <1276988254.133081.1527043373244.ref@mail.yahoo.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1891085057==" Return-path: Received: from sonic303-20.consmr.mail.ne1.yahoo.com (sonic303-20.consmr.mail.ne1.yahoo.com [66.163.188.146]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6BA8E6E3A9 for ; Wed, 23 May 2018 02:43:11 +0000 (UTC) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: "dri-devel@lists.freedesktop.org" List-Id: dri-devel@lists.freedesktop.org --===============1891085057== Content-Type: multipart/alternative; boundary="----=_Part_133080_250834142.1527043373242" ------=_Part_133080_250834142.1527043373242 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi , I=E2=80=99ve been doing some PTN3460 programming under Linux and I have som= e questions regarding on setting the brightness level via DisplayPort Nativ= e Aux. The display device with PTN3460 is connected in DP (display port) to my com= puter.=C2=A0I=E2=80=99m currently looking into the DRM (Direct Rendering Ma= nager) a subsystem of the Linux kernel. It has a methods drm_dp_dpcd_readb,= drm_dp_dpcd_read and drm_dp_dpcd_write.=C2=A0 Do you have any suggestions or advice how to use the kernel driver in DRM i= n regards to how to implement the method drm_dp_dpcd_readb for example? I c= ouldn't not find any test tool examples that implement it. My goal is to create an application that would send/read bytes (brightness = level) to address 0x722 or 0x723. Namedrm_dp_dpcd_readb =E2=80=94 read a single byte from the DPCDSynopsisssi= ze_t drm_dp_dpcd_readb (=C2=A0 =C2=A0 struct drm_dp_aux * aux, =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0unsigned int offset,= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0u8 * valuep); Argumentsaux - DisplayPort AUX channeloffset - address of the register to r= eadvaluep - location where the value of the register will be storedDescript= ionReturns the number of bytes transferred (1) on success, or a negative er= ror code on failure. Regards,John ------=_Part_133080_250834142.1527043373242 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

Hi ,

I=E2=80=99ve been doing some PTN3460 programming under= Linux and I have some questions regarding on setting the brightness level = via DisplayPort Native Aux.

The display device wit= h PTN3460 is connected in DP (display port) to my computer.

= ;

I=E2=80=99m currently looking into the DRM (Direct Rendering Ma= nager) a subsystem of the Linux kernel. It has a methods drm_dp_dpcd_readb,= drm_dp_dpcd_read and drm_dp_dpcd_write.

Do = you have any suggestions or advice how to use the kernel driver in DRM in r= egards to how to implement the method drm_dp_dpcd_readb for example? I coul= dn't not find any test tool examples that implement it.

My goal is to create an application tha= t would send/read bytes (brightness level) to address 0x722 or 0x723.

=

Name

drm_dp_dpc= d_readb =E2=80=94 read a single byte from the DPCD

Synopsis

=

ssize_t drm_dp_dpcd_readb ( struct drm_dp_aux * aux,

= ;unsigned int offset,

&= nbsp; u8 * valuep);

Arguments

aux = - DisplayPort AUX channel

offset - address of the register to rea= d

valuep - location where the value of the register will be store= d

Description

Returns the number of bytes transferred (= 1) on success, or a negative error code on failure.

Regards,

John

------=_Part_133080_250834142.1527043373242-- --===============1891085057== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============1891085057==--