From patchwork Tue Dec 5 09:48:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jocelyn Falempe X-Patchwork-Id: 13479737 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 88D1FC4167B for ; Tue, 5 Dec 2023 09:52:16 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BFBD210E4C2; Tue, 5 Dec 2023 09:52:12 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id D873A10E4B7 for ; Tue, 5 Dec 2023 09:52:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701769929; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YpXXEnOY6Bu6pd6vdiQLVGrNVnugfGHDcxipyCgumU4=; b=FpH1drkv7OX4rW4AG+Ux6srz4dp9Vy8JxvduBa4aMRfDtHE0g4lT9K/KiCPej295ag6W6K qHuWQ8HCDcnHIzJKCWV8FhE2qgwVfL/VXFrZzf0PNNF7g6GyCdEA7V99aR046XimcRO9XD ZHQA7AMyRLgkq0jnRQuSrYJkJfeqgJk= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-312-l4YgEwjjOEOyPYrclyr7JA-1; Tue, 05 Dec 2023 04:52:05 -0500 X-MC-Unique: l4YgEwjjOEOyPYrclyr7JA-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 84B013C23FE6; Tue, 5 Dec 2023 09:52:04 +0000 (UTC) Received: from hydra.redhat.com (unknown [10.39.195.34]) by smtp.corp.redhat.com (Postfix) with ESMTP id C9713492BC7; Tue, 5 Dec 2023 09:52:02 +0000 (UTC) From: Jocelyn Falempe To: dri-devel@lists.freedesktop.org, tzimmermann@suse.de, airlied@redhat.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, daniel@ffwll.ch, javierm@redhat.com, bluescreen_avenger@verizon.net, noralf@tronnes.org Subject: [PATCH v6 2/5] drm/panic: Add a drm panic handler Date: Tue, 5 Dec 2023 10:48:24 +0100 Message-ID: <20231205095051.269841-3-jfalempe@redhat.com> In-Reply-To: <20231205095051.269841-1-jfalempe@redhat.com> References: <20231205095051.269841-1-jfalempe@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: gpiccoli@igalia.com, Jocelyn Falempe Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This module displays a user friendly message when a kernel panic occurs. It currently doesn't contain any debug information, but that can be added later. v2 * Use get_scanout_buffer() instead of the drm client API. (Thomas Zimmermann) * Add the panic reason to the panic message (Nerdopolis) * Add an exclamation mark (Nerdopolis) v3 * Rework the drawing functions, to write the pixels line by line and to use the drm conversion helper to support other formats. (Thomas Zimmermann) v4 * Use drm_fb_r1_to_32bit for fonts (Thomas Zimmermann) * Remove the default y to DRM_PANIC config option (Thomas Zimmermann) * Add foreground/background color config option * Fix the bottom lines not painted if the framebuffer height is not a multiple of the font height. * Automatically register the device to drm_panic, if the function get_scanout_buffer exists. (Thomas Zimmermann) v5 * Change the drawing API, use drm_fb_blit_from_r1() to draw the font. * Also add drm_fb_fill() to fill area with background color. * Add draw_pixel_xy() API for drivers that can't provide a linear buffer. * Add a flush() callback for drivers that needs to synchronize the buffer. * Add a void *private field, so drivers can pass private data to draw_pixel_xy() and flush(). v6 * Fix sparse warning for panic_msg and logo Signed-off-by: Jocelyn Falempe --- drivers/gpu/drm/Kconfig | 22 +++ drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_drv.c | 8 + drivers/gpu/drm/drm_panic.c | 368 ++++++++++++++++++++++++++++++++++++ include/drm/drm_drv.h | 21 ++ include/drm/drm_panic.h | 96 ++++++++++ 6 files changed, 516 insertions(+) create mode 100644 drivers/gpu/drm/drm_panic.c create mode 100644 include/drm/drm_panic.h diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index b7abd436455f..6bf7a5b2f288 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -103,6 +103,28 @@ config DRM_KMS_HELPER help CRTC helpers for KMS drivers. +config DRM_PANIC + bool "Display a user-friendly message when a kernel panic occurs" + depends on DRM && !FRAMEBUFFER_CONSOLE + select FONT_SUPPORT + help + Enable a drm panic handler, which will display a user-friendly message + when a kernel panic occurs. It's useful when using a user-space + console instead of fbcon. + It will only work if your graphic driver supports this feature. + To support Hi-DPI Display, you can enable bigger fonts like + FONT_TER16x32 + +config DRM_PANIC_FOREGROUND_COLOR + hex "Drm panic screen foreground color, in RGB" + depends on DRM_PANIC + default 0xffffff + +config DRM_PANIC_BACKGROUND_COLOR + hex "Drm panic screen background color, in RGB" + depends on DRM_PANIC + default 0x000000 + config DRM_DEBUG_DP_MST_TOPOLOGY_REFS bool "Enable refcount backtrace history in the DP MST helpers" depends on STACKTRACE_SUPPORT diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index b4cb0835620a..100e7cfad3b9 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -73,6 +73,7 @@ drm-$(CONFIG_DRM_PRIVACY_SCREEN) += \ drm_privacy_screen_x86.o drm-$(CONFIG_DRM_ACCEL) += ../../accel/drm_accel.o obj-$(CONFIG_DRM) += drm.o +drm-$(CONFIG_DRM_PANIC) += drm_panic.o obj-$(CONFIG_DRM_PANEL_ORIENTATION_QUIRKS) += drm_panel_orientation_quirks.o diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 3c835c99daad..897146fbda25 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -955,6 +956,9 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags) goto err_unload; } + if (driver->get_scanout_buffer) + drm_panic_register(dev); + DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n", driver->name, driver->major, driver->minor, driver->patchlevel, driver->date, @@ -1001,6 +1005,8 @@ void drm_dev_unregister(struct drm_device *dev) dev->registered = false; + drm_panic_unregister(dev); + drm_client_dev_unregister(dev); if (drm_core_check_feature(dev, DRIVER_MODESET)) @@ -1083,6 +1089,7 @@ static void drm_core_exit(void) unregister_chrdev(DRM_MAJOR, "drm"); debugfs_remove(drm_debugfs_root); drm_sysfs_destroy(); + drm_panic_exit(); idr_destroy(&drm_minors_idr); drm_connector_ida_destroy(); } @@ -1094,6 +1101,7 @@ static int __init drm_core_init(void) drm_connector_ida_init(); idr_init(&drm_minors_idr); drm_memcpy_init_early(); + drm_panic_init(); ret = drm_sysfs_init(); if (ret < 0) { diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c new file mode 100644 index 000000000000..65287f64833a --- /dev/null +++ b/drivers/gpu/drm/drm_panic.c @@ -0,0 +1,368 @@ +// SPDX-License-Identifier: GPL-2.0 or MIT +/* + * Copyright (c) 2023 Jocelyn Falempe + * inspired by the drm_log driver from David Herrmann + * Tux Ascii art taken from cowsay written by Tony Monroe + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + + +MODULE_AUTHOR("Jocelyn Falempe"); +MODULE_DESCRIPTION("DRM panic handler"); +MODULE_LICENSE("GPL"); + +/** + * DOC: DRM Panic + * + * This module displays a user friendly message on screen when a kernel panic + * occurs. This is conflicting with fbcon, so you can only enable it when fbcon + * is disabled. + * It's intended for end-user, so have minimal technical/debug information. + */ + +/* + * Implementation details: + * + * It is a panic handler, so it can't take lock, allocate memory, run tasks/irq, + * or attempt to sleep. It's a best effort, and it may not be able to display + * the message in all situations (like if the panic occurs in the middle of a + * modesetting). + * It will display only one static frame, so performance optimizations are low + * priority as the machine is already in an unusable state. + */ + +/* + * List of active drm devices that can render a panic + */ +struct drm_panic_device { + struct list_head head; + struct drm_device *dev; +}; + +struct drm_panic_line { + u32 len; + const char *txt; +}; + +#define PANIC_LINE(s) {.len = sizeof(s) - 1, .txt = s} + +static struct drm_panic_line panic_msg[] = { + PANIC_LINE("KERNEL PANIC !"), + PANIC_LINE(""), + PANIC_LINE("Please reboot your computer."), + PANIC_LINE(""), + PANIC_LINE(""), /* overwritten with panic reason */ +}; + +static const struct drm_panic_line logo[] = { + PANIC_LINE(" .--. _"), + PANIC_LINE(" |o_o | | |"), + PANIC_LINE(" |:_/ | | |"), + PANIC_LINE(" // \\ \\ |_|"), + PANIC_LINE(" (| | ) _"), + PANIC_LINE(" /'\\_ _/`\\ (_)"), + PANIC_LINE(" \\___)=(___/"), +}; + +static LIST_HEAD(drm_panic_devices); +static DEFINE_MUTEX(drm_panic_lock); + +static void draw_empty_line_map(struct drm_scanout_buffer *sb, size_t top, size_t height, u32 color) +{ + struct iosys_map dst = sb->map; + + iosys_map_incr(&dst, top * sb->pitch); + drm_fb_fill(&dst, sb->pitch, height, sb->width, color, sb->format->cpp[0]); +} + +static void draw_txt_line_map(const struct drm_panic_line *msg, size_t left, size_t top, + struct drm_scanout_buffer *sb, u32 fg_color, u32 bg_color, + const struct font_desc *font) +{ + size_t i; + const u8 *src; + size_t src_stride = DIV_ROUND_UP(font->width, 8); + struct iosys_map dst = sb->map; + size_t end_text; + unsigned int px_width = sb->format->cpp[0]; + + iosys_map_incr(&dst, top * sb->pitch); + drm_fb_fill(&dst, sb->pitch, font->height, left, bg_color, px_width); + iosys_map_incr(&dst, left * px_width); + for (i = 0; i < msg->len; i++) { + src = font->data + (msg->txt[i] * font->height) * src_stride; + drm_fb_blit_from_r1(&dst, sb->pitch, src, src_stride, font->height, font->width, + fg_color, bg_color, px_width); + iosys_map_incr(&dst, font->width * px_width); + } + end_text = (msg->len * font->width) + left; + if (sb->width > end_text) + drm_fb_fill(&dst, sb->pitch, font->height, sb->width - end_text, + bg_color, px_width); +} + +static void draw_empty_line_px(struct drm_scanout_buffer *sb, size_t top, size_t height, u32 color) +{ + unsigned int x, y; + + for (y = 0; y < height; y++) + for (x = 0; x < sb->width; x++) + sb->draw_pixel_xy(x, y + top, color, sb->private); +} + +static void draw_txt_line_px(const struct drm_panic_line *msg, size_t left, size_t top, + struct drm_scanout_buffer *sb, u32 fg_color, u32 bg_color, + const struct font_desc *font) +{ + unsigned int x, y, i; + const u8 *src; + u32 color; + size_t src_stride = DIV_ROUND_UP(font->width, 8); + size_t end_text = msg->len * font->width + left; + size_t right = sb->width > end_text ? sb->width - end_text : 0; + + for (y = 0; y < font->height; y++) { + for (x = 0; x < left; x++) + sb->draw_pixel_xy(x, y + top, bg_color, sb->private); + + for (i = 0; i < msg->len; i++) { + src = font->data + (msg->txt[i] * font->height + y) * src_stride; + for (x = 0; x < font->width; x++) { + color = (src[x / 8] & (0x80 >> (x % 8))) ? fg_color : bg_color; + sb->draw_pixel_xy(x + left + font->width * i, y + top, color, + sb->private); + } + } + + for (x = 0; x < right; x++) + sb->draw_pixel_xy(x + end_text, y + top, bg_color, sb->private); + } +} + +static void draw_empty_line(struct drm_scanout_buffer *sb, size_t top, size_t height, u32 color) +{ + if (sb->draw_pixel_xy) + draw_empty_line_px(sb, top, height, color); + else + draw_empty_line_map(sb, top, height, color); +} + +static void draw_txt_line(const struct drm_panic_line *msg, size_t left, size_t top, + struct drm_scanout_buffer *sb, u32 fg_color, u32 bg_color, + const struct font_desc *font) +{ + if (sb->draw_pixel_xy) + draw_txt_line_px(msg, left, top, sb, fg_color, bg_color, font); + else + draw_txt_line_map(msg, left, top, sb, fg_color, bg_color, font); +} + + +static size_t panic_msg_needed_lines(size_t chars_per_line) +{ + size_t msg_len = ARRAY_SIZE(panic_msg); + size_t lines = 0; + size_t i; + + for (i = 0; i < msg_len; i++) + lines += panic_msg[i].len ? DIV_ROUND_UP(panic_msg[i].len, chars_per_line) : 1; + return lines; +} + +static bool can_draw_logo(size_t chars_per_line, size_t lines, size_t msg_lines) +{ + size_t i; + + for (i = 0; i < ARRAY_SIZE(logo); i++) { + if (logo[i].len > chars_per_line) + return false; + } + if (lines < msg_lines + ARRAY_SIZE(logo)) + return false; + return true; +} + +static size_t get_start_line(size_t lines, size_t msg_lines, bool draw_logo) +{ + size_t remaining; + size_t logo_len = ARRAY_SIZE(logo); + + if (lines < msg_lines) + return 0; + remaining = lines - msg_lines; + if (draw_logo && remaining / 2 <= logo_len) + return logo_len + (remaining - logo_len) / 4; + return remaining / 2; +} + +/* + * Draw the panic message at the center of the screen + */ +static void draw_panic_static(struct drm_scanout_buffer *sb, const char *msg) +{ + size_t lines, msg_lines, l, msg_start_line, remaining, msgi; + size_t chars_per_line; + bool draw_logo; + struct drm_panic_line panic_line; + size_t msg_len = ARRAY_SIZE(panic_msg); + size_t logo_len = ARRAY_SIZE(logo); + u32 fg_color = CONFIG_DRM_PANIC_FOREGROUND_COLOR; + u32 bg_color = CONFIG_DRM_PANIC_BACKGROUND_COLOR; + const struct font_desc *font = get_default_font(sb->width, sb->height, 0x8080, 0x8080); + + if (!font) + return; + + /* Set the panic reason */ + panic_msg[msg_len - 1].len = strlen(msg); + panic_msg[msg_len - 1].txt = msg; + + lines = sb->height / font->height; + chars_per_line = sb->width / font->width; + + msg_lines = panic_msg_needed_lines(chars_per_line); + draw_logo = can_draw_logo(chars_per_line, lines, msg_lines); + msg_start_line = get_start_line(lines, msg_lines, draw_logo); + + fg_color = drm_fb_convert_from_xrgb8888(fg_color, sb->format->format); + bg_color = drm_fb_convert_from_xrgb8888(bg_color, sb->format->format); + + msgi = 0; + panic_line.len = 0; + for (l = 0; l < lines; l++) { + if (draw_logo && l < logo_len) + draw_txt_line(&logo[l], 0, l * font->height, sb, fg_color, bg_color, font); + else if (l >= msg_start_line && msgi < msg_len) { + if (!panic_line.len) { + panic_line.txt = panic_msg[msgi].txt; + panic_line.len = panic_msg[msgi].len; + } + if (!panic_line.len) { + draw_empty_line(sb, l * font->height, font->height, bg_color); + msgi++; + } else if (panic_line.len > chars_per_line) { + remaining = panic_line.len - chars_per_line; + panic_line.len = chars_per_line; + draw_txt_line(&panic_line, 0, l * font->height, sb, fg_color, + bg_color, font); + panic_line.txt += chars_per_line; + panic_line.len = remaining; + } else { + draw_txt_line(&panic_line, + font->width * (chars_per_line - panic_line.len) / 2, + l * font->height, sb, fg_color, bg_color, font); + panic_line.len = 0; + msgi++; + } + } else { + draw_empty_line(sb, l * font->height, font->height, bg_color); + } + } + /* Fill the bottom of the screen, if sb->height is not a multiple of font->height */ + if (sb->height % font->height) + draw_empty_line(sb, l * font->height, sb->height - l * font->height, bg_color); +} + +static void draw_panic_device(struct drm_device *dev, const char *msg) +{ + struct drm_scanout_buffer sb = {0}; + + if (dev->driver->get_scanout_buffer(dev, &sb)) + return; + draw_panic_static(&sb, msg); + if (sb.flush) + sb.flush(sb.private); +} + +static int drm_panic(struct notifier_block *this, unsigned long event, + void *ptr) +{ + struct drm_panic_device *drm_panic_device; + + list_for_each_entry(drm_panic_device, &drm_panic_devices, head) { + draw_panic_device(drm_panic_device->dev, ptr); + } + return NOTIFY_OK; +} + +static struct notifier_block drm_panic_notifier = { + .notifier_call = drm_panic, +}; + +/** + * drm_panic_register() - Initialize DRM panic for a device + * @dev: the DRM device on which the panic screen will be displayed. + */ +void drm_panic_register(struct drm_device *dev) +{ + struct drm_panic_device *new; + + new = kzalloc(sizeof(*new), GFP_KERNEL); + if (!new) + return; + + new->dev = dev; + mutex_lock(&drm_panic_lock); + list_add_tail(&new->head, &drm_panic_devices); + mutex_unlock(&drm_panic_lock); + + drm_info(dev, "Registered with drm panic\n"); +} +EXPORT_SYMBOL(drm_panic_register); + +/** + * drm_panic_unregister() + * @dev: the DRM device previously registered. + */ +void drm_panic_unregister(struct drm_device *dev) +{ + struct drm_panic_device *drm_panic_device; + struct drm_panic_device *found = NULL; + + mutex_lock(&drm_panic_lock); + list_for_each_entry(drm_panic_device, &drm_panic_devices, head) { + if (drm_panic_device->dev == dev) + found = drm_panic_device; + } + if (found) { + list_del(&found->head); + kfree(found); + drm_info(dev, "Unregistered with drm panic\n"); + } + mutex_unlock(&drm_panic_lock); +} +EXPORT_SYMBOL(drm_panic_unregister); + +/** + * drm_panic_init() - Initialize drm-panic subsystem + * + * register the panic notifier + */ +void drm_panic_init(void) +{ + atomic_notifier_chain_register(&panic_notifier_list, + &drm_panic_notifier); +} + +/** + * drm_panic_exit() - Shutdown drm-panic subsystem + */ +void drm_panic_exit(void) +{ + atomic_notifier_chain_unregister(&panic_notifier_list, + &drm_panic_notifier); +} diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h index ea36aa79dca2..293bf6b9f200 100644 --- a/include/drm/drm_drv.h +++ b/include/drm/drm_drv.h @@ -43,6 +43,7 @@ struct dma_buf_attachment; struct drm_display_mode; struct drm_mode_create_dumb; struct drm_printer; +struct drm_scanout_buffer; struct sg_table; /** @@ -401,6 +402,26 @@ struct drm_driver { */ void (*show_fdinfo)(struct drm_printer *p, struct drm_file *f); + /** + * @get_scanout_buffer: + * + * Get the current scanout buffer, to display a panic message with drm_panic. + * The driver should do the minimum changes to provide a linear buffer, that + * can be used to display the panic screen. + * It is called from a panic callback, and must follow its restrictions. + * (no locks, no memory allocation, no sleep, no thread/workqueue, ...) + * It's a best effort mode, so it's expected that in some complex cases the + * panic screen won't be displayed. + * Some hardware cannot provide a linear buffer, so there is a draw_pixel_xy() + * callback in the struct drm_scanout_buffer that can be used in this case. + * + * Returns: + * + * Zero on success, negative errno on failure. + */ + int (*get_scanout_buffer)(struct drm_device *dev, + struct drm_scanout_buffer *sb); + /** @major: driver major number */ int major; /** @minor: driver minor number */ diff --git a/include/drm/drm_panic.h b/include/drm/drm_panic.h new file mode 100644 index 000000000000..c977ab77fba8 --- /dev/null +++ b/include/drm/drm_panic.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 or MIT */ +#ifndef __DRM_PANIC_H__ +#define __DRM_PANIC_H__ + +/* + * Copyright (c) 2023 Jocelyn Falempe + */ + +#include +#include +#include + +struct drm_device; + +/** + * struct drm_scanout_buffer - DRM scanout buffer + * + * This structure holds the information necessary for drm_panic to draw the + * panic screen, and display it. + * If the driver can't provide a linear buffer, it must clear @map with + * iosys_map_clear() and provide a draw_pixel_xy() function. + */ +struct drm_scanout_buffer { + /** + * @format: + * + * drm format of the scanout buffer. + */ + const struct drm_format_info *format; + /** + * @map: + * + * Virtual address of the scanout buffer, either in memory or iomem. + * The scanout buffer should be in linear format, and can be directly + * sent to the display hardware. Tearing is not an issue for the panic + * screen. + */ + struct iosys_map map; + /** + * @width: Width of the scanout buffer, in pixels. + */ + unsigned int width; + /** + * @height: Height of the scanout buffer, in pixels. + */ + unsigned int height; + /** + * @pitch: Length in bytes between the start of two consecutive lines. + */ + unsigned int pitch; + /** + * @private: + * + * In case the driver can't provide a linear buffer, this is a pointer to + * some private data, that will be passed when calling @draw_pixel_xy() + * and @flush() + */ + void *private; + /** + * @draw_pixel_xy: + * + * In case the driver can't provide a linear buffer, this is a function + * that drm_panic will call for each pixel to draw. + * Color will be converted to the format specified by @format. + */ + void (*draw_pixel_xy)(unsigned int x, unsigned int y, u32 color, void *private); + /** + * @flush: + * + * This function is called after the panic screen is drawn, either using + * the iosys_map or the draw_pixel_xy path. In this function, the driver + * can send additional commands to the hardware, to make the buffer + * visible. + */ + void (*flush)(void *private); +}; + +#ifdef CONFIG_DRM_PANIC + +void drm_panic_init(void); +void drm_panic_exit(void); + +void drm_panic_register(struct drm_device *dev); +void drm_panic_unregister(struct drm_device *dev); + +#else + +static inline void drm_panic_init(void) {} +static inline void drm_panic_exit(void) {} + +static inline void drm_panic_register(struct drm_device *dev) {} +static inline void drm_panic_unregister(struct drm_device *dev) {} + +#endif + +#endif /* __DRM_LOG_H__ */