kernel/linux.git/drivers/gpu/drm/msm/dp, branch v5.16.18

drm/msm/dp: Avoid unpowered AUX xfers that caused crashes

2021-11-22T18:16:05+00:00

If you happened to try to access `/dev/drm_dp_aux` devices provided by the MSM DP AUX driver too early at bootup you could go boom. Let's avoid that by only allowing AUX transfers when the controller is powered up. Specifically the crash that was seen (on Chrome OS 5.4 tree with relevant backports): Kernel panic - not syncing: Asynchronous SError Interrupt CPU: 0 PID: 3131 Comm: fwupd Not tainted 5.4.144-16620-g28af11b73efb #1 Hardware name: Google Lazor (rev3+) with KB Backlight (DT) Call trace: dump_backtrace+0x0/0x14c show_stack+0x20/0x2c dump_stack+0xac/0x124 panic+0x150/0x390 nmi_panic+0x80/0x94 arm64_serror_panic+0x78/0x84 do_serror+0x0/0x118 do_serror+0xa4/0x118 el1_error+0xbc/0x160 dp_catalog_aux_write_data+0x1c/0x3c dp_aux_cmd_fifo_tx+0xf0/0x1b0 dp_aux_transfer+0x1b0/0x2bc drm_dp_dpcd_access+0x8c/0x11c drm_dp_dpcd_read+0x64/0x10c auxdev_read_iter+0xd4/0x1c4 I did a little bit of tracing and found that: * We register the AUX device very early at bootup. * Power isn't actually turned on for my system until hpd_event_thread() -> dp_display_host_init() -> dp_power_init() * You can see that dp_power_init() calls dp_aux_init() which is where we start allowing AUX channel requests to go through. In general this patch is a bit of a bandaid but at least it gets us out of the current state where userspace acting at the wrong time can fully crash the system. * I think the more proper fix (which requires quite a bit more changes) is to power stuff on while an AUX transfer is happening. This is like the solution we did for ti-sn65dsi86. This might be required for us to move to populating the panel via the DP-AUX bus. * Another fix considered was to dynamically register / unregister. I tried that at but it got ugly. Currently there's a bug where the pm_runtime() state isn't tracked properly and that causes us to just keep registering more and more. Signed-off-by: Douglas Anderson Reviewed-by: Kuogee Hsieh Reviewed-by: Abhinav Kumar Link: https://lore.kernel.org/r/20211109100403.1.I4e23470d681f7efe37e2e7f1a6466e15e9bb1d72@changeid Signed-off-by: Rob Clark

drm/msm/dp: fix missing #include

2021-10-26T16:31:24+00:00

Some randconfig builds fail when drm/drm_bridge.h is not included implicitly in this file: drivers/gpu/drm/msm/dp/dp_parser.c:279:25: error: implicit declaration of function 'devm_drm_panel_bridge_add' [-Werror,-Wimplicit-function-declaration] parser->panel_bridge = devm_drm_panel_bridge_add(dev, panel); Fixes: 4b296d15b355 ("drm/msm/dp: Allow attaching a drm_panel") Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20211026083254.3396322-1-arnd@kernel.org Signed-off-by: Rob Clark

drm/msm/dp: Support up to 3 DP controllers

2021-10-18T21:28:30+00:00

Based on the removal of the g_dp_display and the movement of the priv->dp lookup into the DP code it's now possible to have multiple DP instances. In line with the other controllers in the MSM driver, introduce a per-compatible list of base addresses which is used to resolve the "instance id" for the given DP controller. This instance id is used as index in the priv->dp[] array. Then extend the initialization code to initialize struct drm_encoder for each of the registered priv->dp[] and update the logic for associating each struct msm_dp with the struct dpu_encoder_virt. A new enum is introduced to document the connection between the instances referenced in the dpu_intf_cfg array and the controllers in the DP driver and sc7180 is updated. Lastly, bump the number of struct msm_dp instances carries by priv->dp to 3, the currently known maximum number of controllers found in a Qualcomm SoC. Signed-off-by: Bjorn Andersson Reviewed-by: Stephen Boyd Link: https://lore.kernel.org/r/20211016221843.2167329-6-bjorn.andersson@linaro.org Signed-off-by: Rob Clark

drm/msm/dp: Allow attaching a drm_panel

2021-10-18T21:28:30+00:00

eDP panels might need some power sequencing and backlight management, so make it possible to associate a drm_panel with an eDP instance and prepare and enable the panel accordingly. Now that we know which hardware instance is DP and which is eDP, parser->parse() is passed the connector_type and the parser is limited to only search for a panel in the eDP case. Signed-off-by: Bjorn Andersson Reviewed-by: Stephen Boyd Link: https://lore.kernel.org/r/20211016221843.2167329-5-bjorn.andersson@linaro.org Signed-off-by: Rob Clark

drm/msm/dp: Allow specifying connector_type per controller

2021-10-18T21:28:29+00:00

As the following patches introduced support for multiple DP blocks in a platform and some of those block might be eDP it becomes useful to be able to specify the connector type per block. Although there's only a single block at this point, the array of descs and the search in dp_display_get_desc() are introduced here to simplify the next patch, that does introduce support for multiple DP blocks. Signed-off-by: Bjorn Andersson Reviewed-by: Stephen Boyd Link: https://lore.kernel.org/r/20211016221843.2167329-4-bjorn.andersson@linaro.org Signed-off-by: Rob Clark

drm/msm/dp: Remove global g_dp_display variable

2021-10-18T21:28:29+00:00

As the Qualcomm DisplayPort driver only supports a single instance of the driver the commonly used struct dp_display is kept in a global variable. As we introduce additional instances this obviously doesn't work. Replace this with a combination of existing references to adjacent objects and drvdata. Reviewed-by: Abhinav Kumar Reviewed-by: Stephen Boyd Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20211016221843.2167329-2-bjorn.andersson@linaro.org Signed-off-by: Rob Clark

drm/msm/dp: Simplify the dp_debug debugfs show function

2021-10-15T23:48:19+00:00

The "dp_debug" show function allocates a buffer and piecemeal appends line by line, checking for buffer overflows etc. Migrate the function to seq_file, to remove all the extra book keeping and simplify the function. Reviewed-by: Stephen Boyd Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20211007190211.3158868-1-bjorn.andersson@linaro.org Signed-off-by: Rob Clark

drm/msm/dp: Use the connector passed to dp_debug_get()

2021-10-15T23:40:09+00:00

The debugfs code is provided an array of a single drm_connector. Then to access the connector, the list of all connectors of the DRM device is traversed and all non-DisplayPort connectors are skipped, to find the one and only DisplayPort connector. But as we move to support multiple DisplayPort controllers this will now find multiple connectors and has no way to distinguish them. Pass the single connector to dp_debug_get() and use this in the debugfs functions instead, both to simplify the code and the support the multiple instances. Reviewed-by: Abhinav Kumar Reviewed-by: Stephen Boyd Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20211015232213.1839472-1-bjorn.andersson@linaro.org Signed-off-by: Rob Clark

drm/msm/dp: Allow sub-regions to be specified in DT

2021-10-15T23:35:39+00:00

Not all platforms has P0 at an offset of 0x1000 from the base address, so add support for specifying each sub-region in DT. The code falls back to the predefined offsets in the case that only a single reg is specified, in order to support existing DT. Reviewed-by: Stephen Boyd Reviewed-by: Abhinav Kumar Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20211001174400.981707-6-bjorn.andersson@linaro.org Signed-off-by: Dmitry Baryshkov Signed-off-by: Rob Clark

drm/msm/dp: Store each subblock in the io region

2021-10-15T20:26:34+00:00

Not all platforms has DP_P0 at offset 0x1000 from the beginning of the DP block. So split the dss_io_data memory region into a set of sub-regions, to make it possible in the next patch to specify each of the sub-regions individually. Reviewed-by: Stephen Boyd Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20211001174400.981707-5-bjorn.andersson@linaro.org Signed-off-by: Dmitry Baryshkov Signed-off-by: Rob Clark