Re: [PATCH v2] drm: Add Grain Media GM12U320 kms driver

Hi,

Thanks for the review!

On 03-06-16 19:27, Thierry Reding wrote:

On Fri, Jun 03, 2016 at 03:06:32PM +0200, Hans de Goede wrote:

...

Grain-media GM12U320 based devices are mini video projectors using USB for both power and video data transport.

This commit adds a kms driver for these devices, including prime support.

This driver is based on the existing udl kms driver, and the gm12u320 fb driver by Viacheslav Nurmekhamitov slavrn@yandex.ru.

Signed-off-by: Hans de Goede hdegoede@redhat.com

Changes in v2: -Rebase on 4.7-rc1 -Sync with udl, bring in any fixes done to udl since v1

This sounds a little nightmarish in the long term. From a cursory look this duplicates a bunch of code that's present in UDL, where the main differences are EDID handling and data transfer. I wonder if we can't find a better way of reusing code than duplicating it.

I was planning on eventually moving the shared code to some kms-usb helper lib, I was thinking it would be good to have more then one user first, but if people prefer me first factoring out some code from udl into a lib I can do that instead.

...

diff --git a/drivers/gpu/drm/gm12u320/gm12u320_connector.c b/drivers/gpu/drm/gm12u320/gm12u320_connector.c

[...]

...

+/*

• • Note this assumes this driver is only ever used with the Acer C120, if we
• • add support for other devices the vendor and model should be parameterized.
• */

+static struct edid gm12u320_edid = {

• .header = { 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 },
• .mfg_id = { 0x04, 0x72 }, /* "ACR" */
• .prod_code = { 0x20, 0xc1 }, /* C120h */
• .mfg_week = 1,
• .mfg_year = 1,
• .version = 1, /* EDID 1.3 */
• .revision = 3, /* EDID 1.3 */
• .input = 0x80, /* Digital input */
• .features = 0x02, /* Pref timing in DTD 1 */
• .standard_timings = { { 1, 1 }, { 1, 1 }, { 1, 1 }, { 1, 1 },

• 	      { 1, 1 }, { 1, 1 }, { 1, 1 }, { 1, 1 } },
  

• .detailed_timings = { {

• .pixel_clock = 3383,
  

• /* hactive = 852, hblank = 256 */
  

• .data.pixel_data.hactive_lo = 0x54,
  

• .data.pixel_data.hblank_lo = 0x00,
  

• .data.pixel_data.hactive_hblank_hi = 0x31,
  

• /* vactive = 480, vblank = 28 */
  

• .data.pixel_data.vactive_lo = 0xe0,
  

• .data.pixel_data.vblank_lo = 0x1c,
  

• .data.pixel_data.vactive_vblank_hi = 0x10,
  

• /* hsync offset 40 pw 128, vsync offset 1 pw 4 */
  

• .data.pixel_data.hsync_offset_lo = 0x28,
  

• .data.pixel_data.hsync_pulse_width_lo = 0x80,
  

• .data.pixel_data.vsync_offset_pulse_width_lo = 0x14,
  

• .data.pixel_data.hsync_vsync_offset_pulse_width_hi = 0x00,
  

• /* Digital separate syncs, hsync+, vsync+ */
  

• .data.pixel_data.misc = 0x1e,
  

• }, {

• .pixel_clock = 0,
  

• .data.other_data.type = 0xfd, /* Monitor ranges */
  

• .data.other_data.data.range.min_vfreq = 59,
  

• .data.other_data.data.range.max_vfreq = 61,
  

• .data.other_data.data.range.min_hfreq_khz = 29,
  

• .data.other_data.data.range.max_hfreq_khz = 32,
  

• .data.other_data.data.range.pixel_clock_mhz = 4, /* 40 MHz */
  

• .data.other_data.data.range.flags = 0,
  

• .data.other_data.data.range.formula.cvt = {
  

• 	0xa0, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20 },
  

• }, {

• .pixel_clock = 0,
  

• .data.other_data.type = 0xfc, /* Model string */
  

• .data.other_data.data.str.str = {
  

• 	'C', '1', '2', '0', 'P', 'r', 'o', 'j', 'e', 'c',
  

• 	't', 'o', 'r' },
  

• }, {

• .pixel_clock = 0,
  

• .data.other_data.type = 0xfe, /* Unspecified text / padding */
  

• .data.other_data.data.str.str = {
  

• 	'\n', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
  

• 	' ', ' ',  ' ' },
  

• } },
• .checksum = 0x40,

+};

Where did you get this from?

I completely made it up, other then for the resolution which is the native resolution of the lcd in the projector

Doesn't this device have a chip that you can query at runtime?

Not to my knowledge.

...

+static int gm12u320_connector_set_property(struct drm_connector *connector,

• 			   struct drm_property *property,
  

• 			   uint64_t val)
  

+{

• return 0;

+}

Just drop it if it doesn't do anything.

Ok, then it should probably be dropped from udl too, I'll check and submit a separate patch for this.

...

+int gm12u320_connector_init(struct drm_device *dev,

• 	    struct drm_encoder *encoder)
  

+{

• struct drm_connector *connector;
• connector = kzalloc(sizeof(struct drm_connector), GFP_KERNEL);
• if (!connector)

• return -ENOMEM;
  

• drm_connector_init(dev, connector, &gm12u320_connector_funcs,

• 	   DRM_MODE_CONNECTOR_Unknown);
  

According to the Grain Media website this chip is a USB 3.0-to-HDMI bridge, so DRM_MODE_CONNECTOR_HDMIA might be a better choice here.

Hmm, where did you find this ? Note I've never actually verified the gm12u320 name this comes from previous reverse engineering work done on the projector.

HDMI for what is in essence a lcd panel seems wrong, maybe lvds if you want to avoid Unknown ?

...

diff --git a/drivers/gpu/drm/gm12u320/gm12u320_drv.c b/drivers/gpu/drm/gm12u320/gm12u320_drv.c

[...]

...

new file mode 100644 index 0000000..eff3a44 --- /dev/null +++ b/drivers/gpu/drm/gm12u320/gm12u320_drv.c @@ -0,0 +1,160 @@ +/*

• • Copyright (C) 2012-2016 Red Hat Inc.
• • This file is subject to the terms and conditions of the GNU General Public
• • License v2. See the file COPYING in the main directory of this archive for
• • more details.
• */

+#include <linux/module.h> +#include <drm/drmP.h> +#include <drm/drm_crtc_helper.h> +#include "gm12u320_drv.h"

+static int gm12u320_driver_set_busid(struct drm_device *d, struct drm_master *m) +{

• return 0;

+}

This is optional, you can drop it.

Idem. as above, then it should probably be dropped from udl too, I'll check and submit a separate patch for this.

Regards,

Hans