From: John Sledge <john_sledget@yahoo.com>
To: "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
Subject: DRM Inquiry DPCD
Date: Wed, 23 May 2018 02:42:53 +0000 (UTC) [thread overview]
Message-ID: <1276988254.133081.1527043373244@mail.yahoo.com> (raw)
In-Reply-To: 1276988254.133081.1527043373244.ref@mail.yahoo.com
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Hi ,
I’ve 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 with PTN3460 is connected in DP (display port) to my computer. I’m currently looking into the DRM (Direct Rendering Manager) 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 regards to how to implement the method drm_dp_dpcd_readb for example? I couldn'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 — read a single byte from the DPCDSynopsisssize_t drm_dp_dpcd_readb ( struct drm_dp_aux * aux,
unsigned int offset, u8 * valuep);
Argumentsaux - DisplayPort AUX channeloffset - address of the register to readvaluep - location where the value of the register will be storedDescriptionReturns the number of bytes transferred (1) on success, or a negative error code on failure.
Regards,John
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next parent reply other threads:[~2018-05-23 2:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1276988254.133081.1527043373244.ref@mail.yahoo.com>
2018-05-23 2:42 ` John Sledge [this message]
2018-05-23 6:41 ` DRM Inquiry DPCD Jani Nikula
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